SECTION ON CARDIOLOGY

FRIDAY, OCTOBER 8,1999

8:15 am-5:15 pmRoom 30, Washington Convention Center

8:15 WelcomeLarry T. Mahoney, MD, FAAP

Abstract PresentationsModerators: Larry T. Mahoney, MD, FAAP andDerek Fyfe, MD, FAAP

1) 8:30 am Evaluation of an Analog Electronic Stetho-scope for Pediatric Telecardiology.Leone Mattioli, MD, FAAP, John Belmont,PhD, Ken Goertz, MD, FAAP and Mari Hag-gart, RN, BSN, Department of Pediatrics,University of Kansas Medical Center, Kan-sas City KS.

2) 8:45 am Inhaled Nitric Oxide is Associated withIncreased Endothelin-1 Levels: A PotentialCause of the Rebound Pulmonary Hyper-tension Phenomenon.Jeffrey M. Pearl, MD, David P. Nelson, MD,PhD, Jenni L. Raake, RRT, Peter B. Manning,MD, Steven M. Schwartz, MD, Thomas P. Shan-ley, MD and Hector R. Wong, MD. Division ofPediatric Cardiothoracic Surgery, Children'sHospital Medical Center, Cincinnati OH.

3) 9:00 am Natural History of Congenital Aortic Ste-nosis as Determined by Serial DopplerEchocardiography.Jennifer H. Lindsey, MD and Howard P. Gutge-sell, MD, FAAP. Department of Pediatrics, Di-vision of Pediatric Cardiology, University ofVirginia Medical Center, Charlottesville VA.

Restrictive Cardiomyopathy in Childhood:Presentation and Timing for CardiacTransplantationM.T. Kimberling, MD, D.T. Balzer, MD, R.Hirsh, MB Ch.B and C.E. Canter, MD. Depart-ment of Pediatrics, Division of Cardiology,Washington University, St Louis MO.

Perioperative Care of Adults with Congen-ital Heart Disease in a Pediatric FacilityAntonio Mott, MD, FAAP, Charles Fraser, Jr,MD, George Reul, MD, Louis Bezold, MD,FAAP, Dean Andropoulos, MD and TimothyFeltes, MD, FAAP. Pediatric Cardiology, An-esthesiology and Congenital Heart Surgery,Baylor College of Medicine, Texas Heart In-stitute and Texas Children's Hospital,Houston TX.

6) 9:45 am Assessment of Systolic and Diastolic Ven-tricular Function in Children ReceivingAnthracyclines-A Quantitative ApproachBenjamin W. Eidem, MD, FAAP, Brian Sapp,MD and Frank Cetta, MD, FAAP. Depart-ment of Pediatrics, Loyola University Med-ical Center, Maywood IL.

7) 10:00 am When Innocent Murmur Seems Likely butDoubts Linger. How Frequently DoesEchocardiography Reveal Heart Disease?David A. Danford, MD, FAAP, Ameeta B.Martin, MD, FAAP, Scott E. Fletcher, MD,FAAP and Carl H. Gumbiner, MD, FAAP.

Joint Section of Pediatric Cardiology, Uni-versity of Nebraska Medical Center andCreighton University School of Medicine,Childrens Hospital (Omaha NE) and St.Elizabeth Hospital (Lincoln NE).

8) 10:15 am Somatic Growth in Children with SingleVentricleMitchell I. Cohen, MD, David Bush, MD, PhD,Gil Wernovsky, MD and Victoria L. Vetter,MD. Divisions of Cardiology, Endocrinol-ogy, and Cardiothoracic Surgery, The Chil-dren's Hospital of Philadelphia and TheUniversity of Pennsylvania School of Med-icine, Philadelphia PA.

10:30 am Break

Abstract presentationsModerators: David Danford, MD, FAAP andThomas S. Klitzner, MD, PhD, FAAP

9) 11:00 am Cardiac Conduction in Mutant Microph-thalmia MiceColin T. Maguire, BS, David E. Fisher, MD andCharles I. Berul, MD, FAAP. Children's Hos-pital-Boston, Dana-Farber Cancer Institute,Harvard Medical School, Boston MA.

10) 11:15 am

11) 11:30 am

12) 11:45 am

Progressive Atrioventricular ConductionBlock in a Mouse Myotonic DystrophyModelCharles I. Berul, MD, FAAP, Colin T. Maguire,BS, Josef Gehrmann, MD and Sita Reddy, PhD.Children's Hospital-Boston, Harvard Med-ical School, Boston MA and University ofSouthern California, Los Angeles CA.

Endothelin-1 Blockade with Bosentan De-creases Post-Reoxygenation VentricularDysfunction and Leukocyte-Mediated In-jury.Jeffrey M. Pearl, MD, Donald W. Thomas, CCP,Jerri L. McNamara, CCP, Jenni L. Taake, RRTand David P. Nelson, MD, PhD. Children'sHospital Medical Center, Cincinnati OH.

Mitochondrial Cardiomyopathy: SpecificEnzymatic and DNA DefectsJose Marin-Garcia, MD, FAAP, Radha Anan-thakrishnan, PhD, Michael J. Goldenthal, PhDand Mary Ella Pierpont, MD, PhD. The Mo-lecular Cardiology Institute, Highland ParkNJ and Department of Pediatrics, Universityof Minnesota, Minneapolis MN.

12:00 pm Lunch

1:30 pm Symposium-Hyperlipidemia in YouthNoninvasive Assessment of the Atheroscle-rotic ProcessLarry T. Mahoney, MD, FAAP (Moderator)Diet and the DISC StudyPeter Kwiterovich, MDPractical Consideration for Diet Modifica-tionLinda Van Horn, PhD, RDDrug TherapyBrian McCrindle, MDPanel Discussion

3:30 pm Break

648 PEDIATRICS Vol. 104 No. 3 September 1999

4) 9:15 am

5) 9:30 am

Abstract PresentationsModerators: Christopher L. Case, MD, FAAPand William B. Moskowitz, MD, FAAP

13) 3:45 pm What is the Yield of Echocardiography inthe Evaluation of Syncope?Saskia Ritter, MD, LuAnn Minich, MD, FAAP,Richard Williams, MD, FAAP, Susan Ether-idge, MD, FAAP, Janet Craig, PNP and LloydTani, MD, FAAP. Department of Pediatrics,University of Utah, Salt Lake City UT.

14) 4:00 pm Cardiac Event Monitoring in Pediatric Pa-tients.Marguerite M. Crawford, MD, Howard P. Gut-gesell, MD, FAAP and Nancy L. McDaniel,MD, FAAP. Division of Pediatric Cardiol-ogy, University of Virginia Health SciencesCenter, Charlottesville VA.

15) 4:15 pm Is Amiodarone More Hepatotoxic in Pa-tients with Fontan Operation?Mayte I. Figueroa, MD and Seshadri Balaji,MRCP. Division of Pediatric Cardiology,Medical University of South Carolina,Charleston SC.

16) 4:30 pm Amiodarone is Safe and Highly Effectiveas Primary Therapy for Tachycardia in In-fancySusan P. Etheridge, MD, FAAP, Janet Craig,PNP. University of Utah and Primary Chil-dren's Medical Center, Salt Lake City UT.

17) 4:45 pm Diagnostic Accuracy of the Screening Elec-trocardiogram in Genotyped Long QTSyndromeMisha D. Miller, BA, Co-burn J. Porter, MDand Michael J. Ackerman, MD, PhD, FAAP.Mayo Medical School, Department of Pedi-atric and Adolescent Medicine, Section ofPediatric Cardiology, Mayo Foundation/Mayo Clinic Rochester, Rochester MN.

18) 5:00 pm Pediatric Syncope: Comparison of Emer-gency Department and Cardiology ClinicEvaluation PracticesVenkat Ramesh, MD, Tammy S. Wieand, MS,Ronn E. Tanel, MD, Mitchell I. Cohen, MD,Victoria L. Vetter, MD and Larry A. Rhodes,MD. The Children's Hospital of Philadel-phia, Philadelphia PA.

5:15 pm

5:30 pm

20) 8:45 am A Prospective Analysis of the Immunoge-nicity of Cryopreserved Non-Valved Allo-grafts Used in Pediatric Cardiac SurgeryJohn P. Breinholt, BS, John A. Hawkins, MD,Linda M. Lambert, BS, Thomas C. Fuller, PhD,Tracie Profaizer and Robert E. Shaddy, MD.Departments of Pediatrics, Surgery and Pa-thology, Primary Children's Medical Centerand the University of Utah, Salt Lake CityUT.

21) 9:00 am In Vivo Electrophysiology Studies in En-dothelial Nitric Oxide Synthase (eNOS)Deficient MiceAmit Rakhit, MD, Colin T. Maguire, BS, JosefGehrmann, MD, Ralph A. Kelly, MD, ThomasMichel, MD, PhD and Charles I. Berul, MD,FAAP. Children's Hospital, Boston MA.

22) 9:15 am The Emergency Center vs the ComputerWhich is the Better Electrocardiographer?Christopher S. Snyder, MD, Richard A. Fried-man, MD, FAAP, Arnold L. Fenrich, MD,FAAP, Kelly O'Reilly, MS, Scott Reeves, MDand Naomi J. Kertesz, MD, FAAP. Texas Chil-dren's Hospital/Baylor College of Medi-cine, Houston TX.

23) 9:30 am

24) 9:45 am

25) 10:00 am

Adjoum

Section on Cardiology, Executive Commit-tee Meeting

26) 10:15 am

SATURDAY, OCTOBER 9

8:30 am-5:30 pmRoom 30, Washington Convention Center

Young Investigator Presentations

19) 8:30 am

Moderators: Thomas S. Klitzner, MD, PhD,FAAP and Reginald L. Washington, MD,FAAP

The Early Profile of Myocardial Dysfunc-tion in Chicken Embryos After NeuralCrest AblationHong Jin, MD, Margaret Kirby, PhD and LindaLeatherbury, MD, FAAP. Department of Pe-diatrics, IMMAG Developmental Biology,Medical College of Georgia, Augusta GA.

Doppler Characterization of Dorsal AorticBlood Flow in the Mouse Embryo: InsightsInto the Early Developing CirculationColin K. Phoon, MD, FAAP, Orlando Aristizabal,PhD and Daniel H. Turnbull, PhD. PediatricCardiology Program and Skirbail Institute ofBiomolecular Medicine, New York UniversitySchool of Medicine, New York NY.

Comparison of Holter Results Ordered byPediatric Cardiologists Versus Pediatri-cians in Patients Without Known HeartDiseaseElise M. Riddle, MD, Naomi J. Kertesz, MD,FAAP, Arnold L. Fenrich, MD, FAAP andRichard Friedman, MD, FAAP. Baylor Col-lege of Medicine, Texas Children's Hospital,Houston TX.

Lack of Electrophysiologic Phenotype inImmature Familial Hypertrophic Cardio-myopathy MiceLaura M. Bevilacqua, MD, Colin T. Maguire, BS,JosefGehrnann, MD, Christine E. Seidman, MD,Jonathan G. Seidman, PhD and Charles L Berul,MD, FAAP. Children's Hospital, Boston,Howard Hughes Medical Institutions, Har-vard Medical School, Boston MA.

Coarctation Index: A Novel Approach toIdentify Aortic Arch Obstruction in In-fants with Hypoplastic Left Heart Syn-drome After the Norwood ProcedureMatthew S. Lemler, MD, FAAP, Thomas M.Zellers, MD, FAAP, Katherine A. Harris,RDCS and Claudio Ramaciotti, MD. Depart-ment of Pediatrics, University of TexasSouthwestem Medical School, Dallas TX.

10:30 am Break

Abstract PresentationsModerators: Roger Mee, MB, ChB, FRACS,FAAP and John W.M. Moore, MD, FAAP

27) 10:45 am Conversation of Atriopulmonary or LateralAtrial Tunnel Cavopulmonary Anastomo-

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sis to Extracardiac Conduit Cavopulmo-nary AnastomosisJ.A.M. van Son, MD, F. W. Mohr, MD, J.Hambsch, MD, P. Schneider, MD and G.S.Haas, MD. University of Leipzig, Leipzig,Germany.

28) 11:00 am Impact of Initial Palliation on Outcome inPatients with Pulmonary Atresia and In-tact Ventricular Septum: A Two InstitutionStudyCathryn S. Finch, MD, Zahid Amin, MD,James M Berry, RDMS, William B. Strong,MD, John L. Bass, MD, Holland V. Moore, MDand John F. Foker, MD. Department of Pedi-atrics, Medical College of Georgia, Augustaand University of Minnesota, Minneapolis.

29) 11:15 am Pediatric Cardiac Surgery in a Low Vol-ume Institution: Quality AssessmentRodolfo Neirotti, MD, FETCS, Donald Mal-colm, MD, Dominic Sanfilippo, MD, DonaldJones, DO, Gwendolyn Fosse, RN, BSN andThomas Steffens, CCP. DeVos Children'sHospital, Grand Rapids MI.

30) 11:30 am Late Results After Repair of Complete A-VCanal: 25-Year Follow-upJ.A. Dearani, F.J. Puga, H.V. Schaff, P.W.O'Leary, D.J. Driscoll and G.K. Danielson.Mayo Clinic, Department of Cardiac Sur-gery, Rochester MN.

31) 11:45 am Randomized, Controlled Trial of InhaledNitric Oxide Following Surgery for Con-genital Heart DiseaseRonald W. Day, MD, FAAP. University ofUtah and Primary Children's Medical Cen-ter, Salt Lake City UT.

32) 12:00 pm Intra-aortic Balloon Pumping in Infantsand Children: A Ten-year ExperienceJohn A. Hawkins, MD, L. LuAnn Minich, MD,FAAP, Lloyd Y. Tani, MD, FAAP, George M.Pantalos, PhD, Gregory B. Di Russo, MD andEdwin C. McGough, MD. Departments of Pe-diatrics and Surgery, Primary Children'sMedical Center and University of Utah, SaltLake City UT.

33) 12:15 pm Differences in Incidence of Infant Congen-ital Heart Procedures from a MulticenterConsortiumLee A. Pyles, FAAP, Stanley Einzig, William A.Neal, FAAP and James H. Moller, FAAP. Uni-versity of Minnesota MN and West VirginiaUniversity, Morgantown WV.

12:30 pm Lunch

2:00 pm Symposium-The ICU Management of theChild with Congenital Heart DiseaseSponsored by Sections on Cardiology, Con-genital Heart Surgery, and Critical CareModerator: Roger Mee, MB, ChB, FRACS,FAAP and Niranjan Kissoon, MD, FAAPPostoperative Management of PulmonaryHypertension.Jon Meliones, MDPre/Postoperative management of HLHS/NorwoodEdward Bove, MDPostoperative Management of Cavopulmo-nary AnastomosisDes Bohn, MD,

Myocardial and Central Nervous SystemDysfunction after Cardiopulmonary BypassGil Wernovsky, MDPanel Discussion

4:15 pm Break

4:30 pm Section Business MeetingChair: J. Timothy Bricker, MD, FAAP

5:30 pm Adjourn

7:00 pm Section on Cardiology Banquet (Advanceregistration required for tickets)

SUNDAY, OCTOBER 10

8:30 am-4:45 pmRoom 30, Washington Convention Center

8:30 am Presentation of AAP Section on Cardiol-ogy 1999 Young Investigator Awards in Ba-sic and Clinical ScienceJ. Timothy Bricker, MD, FAAP

8:45 am Presentation of AAP Section on Cardiol-ogy 1999 Research Fellowship Award toBenjamin L. Siu, MD and Presentation ofResults of AAP Section on Cardiology 1998Research Fellowship Award by AndrewRobinson, MDThe 1999-2000 Research Fellowship Award issupported by an educational grantfrom WiltonW. Webster, Jr. The 1998-99 Award is sup-ported by an educational grantfrom the Friendsof Children Corp. Fund.

9:15 am Presentation of the 1999 Founders Awardto Samuel Kaplan, MD, FAAP.

9:30 am Founder's AddressRichard Meyer, MD

10:30 am Break

Abstract PresentationsModerators: Christopher L. Case, MD, FAAPand Derek A. Fyfe, MD, PhD, FAAP

34) 10:45 am Incidence and Predictors of Supradia-phragmatic Systemic Venous CollateralFormation Following the Fontan Opera-tionHoward S. Weber, MD, FAAP, Steven Zang-will, MD, FAAP and Stephen E. Cyran, MD,FAAP. Department of Pediatrics (Cardiolo-gy), Pennsylvania State University Chil-dren's Hospital, Hershey PA.

35) 11:00 am Extracardiac Repair of Complex UnroofedCoronary SinusJ.A.M. van Son, MD, G.S. Haas, MD, J. Hamb-sch, MD and F.W. Mohr, MD. Herzzentrum,University of Leipzig, Leipzig, Germany.

36) 11:15 am Closure of Single and Multiple AtrialCommunications Using the AmplatzerSeptal OccluderWolfgang A.K. Radtke, MD, B. Rush Waller,MD, Girish Shirali, MD, FAAP and Henry B.Wiles, MD, FAAP. Medical University ofSouth Carolina, Charleston SC.

37) 11:30 am Five-Year Experience with Coil Occlusionof Patent Ductus Arteriosus Using LongGianturco Coils with 4-6 LoopsWolfgang A.K. Radtke, MD. Medical Univer-sity of South Carolina, Charleston SC.

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38) 11:45 am The Use of Telemedicine in Patients withPossible Congenital Heart Disease to Op-timize Care and Facilitate TransportKenneth M. Shaffer, MD, Howard Heiman,MD, FAAP, John Brownlee, MD, FAAP, HerbWitley, MD, FAAP. San Antonio Military Pe-diatric Center (SAMPC), Lackland AFB TX.

39) 12:00 pm Cardiac Troponin I Levels in Pediatric Pa-tients with Acquired Heart DiseaseRichard V. Williams, MD, FAAP, Timothy M.Olson, MD, FAAP, Paul C. Young, MD, FAAPand Robert E. Shaddy, MD, FAAP. PrimaryChildren's Medical Center, University ofUtah, Salt Lake City UT.

12:15 pm Lunch

1:30 pm Symposium-Acquired Cardiac Disease InChildrenModerator: Reginald L. Washington, MD,FAAPCardiac Aspects of HIVSteven E. Lipshultz, MDMyocarditisJeffrey Towban, MDKawasaki Disease UpdateMasato Takahashi, MDAnthracycline ToxicityRobert E. Shaddy, MD, FAAPPanel Discussion

3:30 pm Break

Abstract PresentationsModerators: Larry T. Mahoney, MD, FAAP andDavid A. Danford, MD, FAAP

40) 3:45 pm Hemodynamic Disturbances in Human Fe-tuses with Obstructive Congenital HeartDiseaseMichael R. Brumund, MD and William A. Lu-tin, MD, PhD, FAAP. Department of Pediat-rics, Section of Pediatric Cardiology, Medi-cal College of Georgia, Augusta GA.

41) 4:00 pm Course of Left Ventricular Function andDimensions Before and After Aortic ValveReplacement for Chronic Aortic Regurgi-tationAnne G. Farrell, MD, Roger A. Hurwitz, MD,FAAP and Timothy M. Cordes, MD. Depart-ment of Pediatrics, Indiana UniversitySchool of Medicine, Indianapolis IN.

42) 4:15 pm Contrast Echo During Cardiac Catheteriza-tion for the Diagnosis of PulmonaryAVMs in Patients with Fontan/Hemi-Fon-tan ConnectionMarcus S. Schamberger, MD, Anne G. Farrell,MD, Eric S. Ebenroth, MD, Timothy M.Cordes, MD, Robert K. Darragh, MD and San-jay R. Parikh, MD. Department of Pediatrics,Indiana University School of Medicine, In-dianapolis IN.

43) 4:30 pm Echocardiographic Predictors of Restric-tive Interatrial Communication RequiringBalloon Atrial Septostomy in Infants withHypoplastic Left Heart SyndromeNeda Mulla, MD, FAAP, Anne Osher, DVM,Lawrence Beeson, DrPH and Renae Larsen,MD, FAAP. Loma Linda Children's Hospi-tal, Loma Linda CA.

4:45 pm Adjourn

CARDIOLOGY SESSION

1EVALUATION OF AN ANALOG ELECTRONICSTETHOSCOPE FOR PEDIATRIC TELECARDIOLOGY.

Leone Mattioli, MD, FAAP, John Belmont, PhD, Ken Goertz,MD, FAAP and Mari Haggart, RN, BSN. Dept of Peds, Univ ofKansas Medical Center, Kansas City, KS 66160-7330.

Objective: To test the reliability and diagnostic validity of anarrow-bandwidth electronic stethoscope used for pediatric tele-cardiology between the hospital and public schools.

Materials and Methods: Two pediatric cardiologists participated.One used his own acoustic stethoscope (AS) as part of the routineoutpatient examination. The other used a remote analog electronicstethoscope (ES) connected by ordinary telephone line to theexamination room. The study nurse manipulated the stethoscopechestpiece as directed by the remote examiner via intercom. Forthis conservative trial the remote examiner was not briefed aboutpatient's history and neither saw nor spoke with the patient. For46 consecutive pediatric cardiology outpatients (age: mean 10.8,median 10.3, SD 7.1) the examiners made independent judgmentsregarding heart sounds and murmurs, heart disease, necessity ofechocardiography, and provisional diagnosis. The Kappa statistic(K) indexed inter-examiner agreement (reliability) for dichoto-mous variables. Validity was measured by assessing the ES'sheart-disease detection accuracy using echocardiography as thegold standard (N=36).

Results: There was satisfactory ES/AS agreement on presence ofheart disease (K=0.63) and need for follow-up echocardiography(K=0.64). There was also satisfactory agreement on presence ofmurmur (K=0.85), organic murmur (K=0.82), functional murmur(K=0.75), diastolic murmur (K=0.75), systolic murmur (K=0.78),and some specific murmurs and heart sounds: Vibratory (K=0.76),diastolic aortic (K=0.81), diastolic pulmonic (K=0.73) and aorticclick (K=0.64). For other specific murmurs and heart soundsinter-examiner agreement was low (K<0.60) or could not be com-puted for lack of prevalence. Taking the latest echo-cardiogram asgold standard for presence of disease, ES had overall accura-cy=83%, sensitivity=88%, specificity=75%. Heart-disease detec-tion errors were found primarily in the youngest patients(P<0.03). For those age .5 yr, accuracy=92%, sensitivity= 94%,specificity=88%.

Conclusions: The analog ES used with ordinary telephonelines provided reliable, valid screening for pediatric heart dis-ease, especially for patients age >-5 yr. However, for somespecific sounds and murmurs, agreement with AS was unsat-isfactory. A single adult-size diaphragm was used for all pa-tients, which may partly account for the relatively poor perfor-mance among the youngest. Interchangeable diaphragms,conversation with the parent/patient, and use of video to vi-sualize the precordium would probably improve overall per-formance. We regard the analog ES as a highly satisfactory,inexpensive tool for pediatric telecardiology.

2INHALED NITRIC OXIDE IS ASSOCIATED WITHINCREASED ENDOTHELIN-1 LEVELS: A POTENTIALCAUSE OF THE REBOUND PULMONARY HYPERTENSIONPHENOMENON.

Jeffrey M. Pearl, M.D., David P. Nelson, M.D., Ph.D., Jenni L.Raake, R.R.T., Peter B. Manning, M.D., Steven M. Schwartz,M.D., Thomas P. Shanley, M.D., Hector R. Wong, M.D. Chil-dren's Hospital Medical Center, Cincinnati, OH

Background: Endothelin-1 has been implicated as a cause ofacute pulmonary hypertension (PHTN). Inhaled nitric oxide (iNO)has emerged as frontline therapy for PHTN, including PHTN

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following repair of congenital heart disease. Proposed advantagesof iNO include its lack of significant systemic hemodynamic ef-fects, and its relative 'safety'. However, 'rebound' PHTN has beendescribed when inhaled NO is weaned, suggesting either im-paired endogenous NO production or elevated levels of vasocon-stricting agents such as ET-1. ET-1 and NO are known to cross-talk, and it is possible that iNO may affect levels of ET-1. Thisclinical study was undertaken in order to determine the effects ofinhaled NO on levels of ET-1.

Methods: Group 1- Fifteen infants and children with congenitalheart disease (age 3 d-23 mos) requiring iNO for post-CPB PHTN.Arterial blood was obtained prior to iNO, at several time pointsduring, and 24 hours following cessation of inNO. Group 2 con-sisted of ten adult medical patients placed on iNO therapy, andGroup 3 included six infants post-CPB who were at risk for PHTNbut who did not require iNO.

Results: In Group 1, the average increase in ET-1 levels was 48%by 12 hrs of iNO therapy (mean average values= 3.94 pg/ml vs.2.83 pg/ml), and levels remained elevated at 48 hours. Withcessation of iNO ET-1 levels decreased an average of .59 pg/ml,from 107% of baseline to 86% of baseline. In Group 2, ET-1 levelsincreased above baseline by an average of 44%, 61%, 51%, and 50%at 2, 12, 24, and 48 hours (mean average values= 3.25, 3.3, 3.1, and3.0 pg/ml compared with baseline of 2.33pg/ml). Prior to cessa-tion of iNO, ET-1 levels were 124% of baseline (2.89 pg/ml) andfell dramatically to 54% of baseline (1.26 pg/ml) within 24 hoursof discontinuing iNO. In Group 3, ET-1 levels decreased by anaverage of 24% and 35% at 12 and 24 hours post-op. (2.29, 1.68,1.21 pg/ml at baseline, 12, and 24 hours).

Conclusion: ET-1 levels increase by as much as 61% followinginstitution of inhaled NO therapy. The increase in ET-1 does notappear to be a result of CPB as levels did not increase innon-treated patients post-CPB, but did occur in non-surgicaladult patients. These data suggest that iNO results in an in-crease in systemic ET-1 levels. Levels decrease back towardsbaseline after 48 hours, and decrease abruptly when iNO isstopped. This increase in ET-1 may explain part of the reboundphenomenon seen when attempting to wean iNO, and suggeststhat once iNO therapy is begun, it should be continued for atleast 48 hours until ET-1 levels begin to decrease back towardsbaseline.

3NATURAL HISTORY OF CONGENITAL AORTICSTENOSIS AS DETERMINED BY SERIAL DOPPLERECHOCARDIOGRAPHY.

Jennifer H. Lindsey, MD, and Howard P. Gutgesell, MD, FAAP.Department of Pediatrics, Division of Pediatric Cardiology, Uni-versity of Virginia Medical Center, Charlottesville, Virginia.

Background: Our current understanding of the natural history ofcongenital aortic stenosis is derived from catheter-based studieswhich have shown progression of disease severity over time. Todate, there are few studies based on non-invasive methods illus-trating the natural history of congenital aortic stenosis. This studyevaluates the progression of congenital aortic stenosis based onserial Doppler echocardiography. Methods: Doppler echocardio-grams of 102 pediatric patients with valvular AS were reviewed.All patients had at least two Doppler echocardiograms prior toany intervention for AS. Ages ranged from 1 day to 19 years old,and the average interval of follow up was 5.7 years (range 1 monthto 14.2 years).

Results: Transvalvar Doppler gradients at initial evaluationranged from 5 to 80 mmHg. Gradients at follow up evaluationranged from 7 to 96 mmHg. Over the course of follow up, 64patients had an increase in their transvalvar gradient, and in 18of these patients, the increase was > 20 mmHg (maximal gra-dient increase 49 mmHg). In 32 patients, the gradient decreasedduring follow up. The likelihood of progression of congenital

AS was related to the age at initial evaluation. Among the 33patients who were 2 years old or younger at the time of initialevaluation, 12 (36%) had an increase of more than 20 mmHg intheir aortic gradient. However, in the 69 patients over 2 yearsold at time of initial evaluation, only 5 (8%) patients had greaterthan 20 mmHg increase in aortic gradient over the period offollow up. The likelihood of progression of AS and need forintervention was likewise related to the severity of aortic valvegradient at initial evaluation. Of the 95 patients with gradientsless than 50 mmHg at initial evaluation, only 14 (14%) pro-gressed to gradients of greater than 60 mmHg over the periodof follow up. Of the 8 patients who ultimately required inter-vention, 6 patients had initial gradients of > 40 mmHg, and 4patients had initial gradients 2 60 mmHg.

Conclusion: Contrary to earlier studies based on serial cardiaccatheterizations, congential aortic stenosis is not always pro-gressive; early age at diagnosis and higher initial gradientappear to be risk factors for ultimate need for intervention.

4RESTRICTIVE CARDIOMYOPATHY IN CHILDHOOD:PRESENTATION AND TIMING FOR CARDIACTRANSPLANTATION.

M.T. Kimberling M.D., D.T. Balzer M.D., R. Hirsch M.B. Ch.B.,C.E. Canter M.D., Washington University, St. Louis, MO.

Background: Restrictive cardiomyopathy (RCM) is rarely seen inchildren. Limited experience has suggested that elevation of pul-monary vascular resistance (Rp) is so commonly observed thatchildren with RCM should be listed for transplantation at the timeof diagnosis.

Methods: In the past 10 years, 9 children with RCM have beenrefered for evaluation at Washington University. RCM was de-fined by 1) marked biatrial dilitation, 2) normal LV chamber sizeand ejection fraction (>50%), and 3) LV end-diastolic pressure >15 mmHg. Presenting symptoms included palpitations (2), chestpain (2), exertional shortness of breath (3), abdominal pain (1), andcardiac arrest (1). All patients underwent cardiac catheterizationas part of their evaluation.

Results: 4/9 had a normal pulmonary vascular resistance (Rp)index (<3 WU/m2) at the time of diagnosis. Median intervalfrom diagnosis to evaluation for transplant was 68 months(range 2-100 months). At the time of evaluation for transplant,6/9 had elevated Rp index (median= 10.6 WU/m2, range 3.8-24WU/m2). Median transpulmonary gradient (TPG) for these 6was 25 mmHg (range 17-30 mmHg). All 6 demonstrated re-versible Rp index and 5/6 had reversable TPG with NitricOxide (NO) administration. In 2/6 NO was the only mediator todemonstrate Rp reversibility. The median best Rp index andTPG was 3.17 WU/m2 and 15 mmHg respectively. Only onepatient did not achieve a Rp index <5 WU/m2. The 4 patientswith normal Rp index at time of diagnosis were followed for amean of 80 months (range 60-100 months) and only 1/4 hadmild Rp elevation (4.8 WU/m2) at time of transplant evaluation.7/9 have been successfully transplanted to date and all havebeen documented to have normal Rp index and TPG<15 mmHgwithin the first year after transplantation.

Conclusion: These data suggest increased Rp associated with RCMin childhood is usually reversible and NO is the optimal mediator totest for Rp reversibility. RCM in childhood was frequently associatedwith normal Rp at time of diagnosis and in those patients progres-sion of Rp did not occur with follow-up of 5 years or greater. Theseresults, if confirmed in larger patient populations, would suggestdiagnosis of RCM in childhood, per se, is not an indication forprompt transplantation.

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5PERIOPERATIVE CARE OF ADULTS WITH CONGENITALHEART DISEASE IN A PEDIATRIC FACILITY.

Antonio Mott, MD, FAAP, Charles Fraser, Jr., MD, GeorgeReul, MD, Louis Bezold, MD, FAAP, Dean Andropoulos, MD,Timothy Feltes, MD, FAAP. Pediatric Cardiology, Anesthesi-ology and Congenital Heart Surgery, Baylor College of Medi-cine, Texas Heart Institute and Texas Children's Hospital,Houston, TX.

Background: An increasing number of patients (pts) with con-genital heart disease (CHD) present for cardiothoracic surgeryduring adulthood. These pts are often cared for in a pediatricfacility. The purpose of this project is to describe the operativeoutcome and perioperative course of a large cohort of adult ptswho have undergone cardiothoracic surgery at a tertiary pediatrichospital.

Methods: Our clinical database was used to identify all adultCHD pts (>18 yr) who had undergone cardiothoracic surgerybetween 1/95 and 1/99 at our institution. Data retrieved includedpt demographics, cardiac dx, previous & current surgical proce-dures, perioperative complications, hospital length of stay(HLOS), postoperative length of stay (POLOS), and outcome. Pro-cedures were divided into 3 treatment groups. Group 1: pts un-derwent initial insertion or replacement of a pacemaker system;Group 2: pts underwent palliative or definitive cardiac operations;Group 3: pts underwent other types of thoracic procedures. CPRevents = need for CPR + /or emergent cardioversion. Earlydeath = <30d after surgery.

Results: 83 procedures were performed in 74 pts during thestudy period. Early mortality was 7.2%. There were 2 latedeaths. Group 1 (n=19): mean age was 26.6 yr (20-56 yr). Themedian HLOS was 7.5 d (2-25 d) & median postoperative LOSwas 3 d (2-33 d). Complications included: pulmonary arterythrombus & transfer to adult hospital (1) and CPR events (1).There was 1 early death (5%). Group 2 (n=57): mean age was26.6 yr (18-72 yr). Each pt averaged 1.4 previous operativeprocedures. Current operative procedures included: AV valverevision/replacement (n= 10), semilunar valve revision/re-placement (11), Fontan procedure (9), RV-PA conduit (8), ASDclosure (6), and other (12). The median HLOS was 9 d (3-39 d)and the median POLOS was 7 d (2-36 d). Complications in-cluded re-operation for bleeding (3) and ECMO (1). 5 pts hadnew onset postoperative arrhythmias (9%) that required treat-ment: atrial fib/flutter (2), ventricular tachycardia (2), CAVB(1), 20 AVB (1). Transient peripheral neurologic deficits wereobserved (4). 1 pt sustained hypoxic-ischemic encephalopathyprogressing to EEG silence. 5 pts were treated for depression. 1pt required transfer to an adult hospital for extended care.There were 13 CPR events (4 pts) or 23 events/100 procedures.There were 5 early deaths (9%) and 2 late deaths. Group 3 (n= 7):mean age was 23.5 yr (18-34 yr). The median HLOS was 24 d(3-40 d) and median POLOS was 8 d (2-28 d). Proceduresincluded sternal wire removal (2), open lung biopsy (1), peri-cardial window (1), right lung lobectomy (1), AV fistula cre-ation (1), and sternotomy debridement (1). 1 pt had postoper-ative recurrent pneumothoraces. There were no deaths or CPRevents.

Conclusions: 1) Cardiothoracic procedures performed on adultCHD pts at a pediatric facility can be performed with accept-able mortality; 2) New onset arrhythmias necessitating treat-ment are relatively common among adults undergoing cardiacsurgery; 3) Postoperative depression should be anticipated inthis group of pts, 4) Despite acceptable outcomes, the numberof CPR events in the CHD adult undergoing cardiac surgery issignificant.

6ASSESSMENT OF SYSTOLIC & DIASTOLICVENTRICULAR FUNCTION IN CHILDREN RECEIVINGANTHRACYCLINES-A QUANTITATIVE APPROACH.

Benjamin W. Eidem M.D., FAAP, Brian Sapp M.D., Frank CettaM.D., FAAP, Department of Pediatrics, Loyola University MedicalCenter, Maywood, IL

Background: Use of anthracycline antibiotics are common inchemotherapeutic regimens for treatment of childhood malignan-cies. Studies have documented the long-term cardiotoxic effects ofthese agents on cardiac performance in cumulative doses in excessof 450 mg/m2. Routine noninvasive assessment of cardiac functioncurrently relies on serial echocardiographic measurement of leftventricular systolic function (fxn), namely ejection fraction. Quan-titative assessment of left ventricular diastolic fxn and right ven-tricular fxn are not routinely performed in these pts. A myocardialperformance index (MPI) has been reported in pediatric and adultstudies which is a simple, Doppler-derived, non-geometric mea-surement of global (ie systolic and diastolic) ventricular fxn. TheMPI = [(Isovolumic contraction time) + (isovolumic relaxationtime)] / (ejection time). The purpose of this study was to seriallyassess the impact of anthracyclines on global ventricular fxn (asassessed by the MPI) for both the LV and RV and to compare thiswith standard echocardiographic measurements of ventricularfxn.

Methods: LV and RV MPI were serially measured in 26 patientsreceiving adriamycin. In addition, standard echocardiographicmeasurements of fxn were performed, including M-mode and 2-Dejection fraction, shortening fraction, and mitral inflow Doppler.These data were compared to each patient's baseline functionalassessment prior to initiation of anthracyclines and to a group ofnormal pediatric controls. Statistical comparisons were made be-tween groups using unpaired t-tests.

Results: Serial results for 26 study pts are shown below. Meanduration of follow-up was 24 months. Mean total anthracyclinedose = 285 mg/M2. Table: Cumulative Adriamycin dose (mg/M2)

Baseline 0-50 51-100

LV MPI 0.37 (.07) 0.39 (.09) 0.40 (.09)LV EF (%) 62 (7) 64 (11) 57 (7)LV ICT (ms) 42 (17) 43 (14) 48 (23)LV IRT (ms) 55 (16) 65 (18) 59 (16)Mitral E/A 2.0 (1.0) 1.8 (0.4) 2.0 (0.6)RV MPI 0.30 (.06) 0.30 (.06) 0.32 (.05)

101-200 201-300 301-400

0.41 (.12) 0.42 (.08) 0.50 (.15)58 (9) 57 (10) 57 (9)50 (22) 46 (14) 59 (15)56 (17) 58 (12) 59 (20)1.7 (0.4) 1.6 (0.3) 1.7 (0.7)0.31 (.07) 0.33 (.08) 0.27 (.07)

No statistical difference was present between 154 normal pedi-atric controls (ages 3-18 yrs, mean age 9.3 yrs) and the baselineexams in study patients (age 6 mos-17 yrs, mean age 9.3 yrs) foreither the LV MPI (0.37 vs 0.35 in controls, p=NS) or RV MPI (0.30vs 0.33 in controls, p=NS). With cumulative anthracycline dos-age > 300 mg/M2, the LV MPI was significantly elevated despitenormal ejection fraction and other standard measurements ofventricular fxn (LV MPI = 0.50 vs 0.37 baseline, p<0.001). Nosignificant change in RV MPI was seen with increasing anthracy-cline dosage. In 4 study pts who developed LV EF < 45%, the LVMPI was significantly elevated prior to other standard measure-ments of ventricular fxn (mean LV MPI = 0.74 in these 4 pts).

Conclusions: Standard echocardiographic measurements of sys-tolic ventricular function in patients receiving anthracyclines may

SUPPLEMENT 653

miss early signs of ventricular dysfunction at cumulative anthra-cycline dosages significantly less than 450 mg/M2. The MPI, be-cause it is a simple and reproducible Doppler measure of bothsystolic and diastolic ventricular performance, is a promising se-rial tool to quantitatively assess ventricular function. Further long-term serial follow-up in these patients with the MPI deservesongoing investigation.

7WHEN INNOCENT MURMUR SEEMS LIKELY BUTDOUBTS LINGER. HOW FREQUENTLY DOESECHOCARDIOGRAPHY REVEAL HEART DISEASE?

David A. Danford, MD, FAAP, Ameeta B. Martin, MD, FAAP,Scott E. Fletcher, MD, FAAP, and Carl H. Gumbiner, MD, FAAP.Joint Section of Pediatric Cardiology, University of NebraskaMedical Center and Creighton University School of Medicine,Childrens Hospital (Omaha, NE) and St. Elizabeth Hospital (Lin-coln, NE).

Objectives. Discovery of the incidence and nature of heart dis-ease identified among children with murmurs clinically ambiguousto the expert examiner, and elucidation of clinically recognizablefeatures which correlate with the discovery of actual heart diseasein this group. Design. Prospective, blinded study of diagnosticaccuracy of the expert examination was made using echocardiog-raphy (echo) as the diagnostic standard. Setting. Pediatric cardiol-ogy outpatient department. Patients. 804 outpatients with heartmurmur under 21 years old, without prior echo or pediatric car-diology consultation. Intervention. Echo as clinically indicated forevaluation of heart murmur of uncertain cause. Measurements.Expert examiners' clinical diagnoses and echo results in patients(pts) grouped by the examiner's level of suspicion of heart disease,by age of pt, and by indication for echo. Outcome Measures. Clinicaldiagnoses were compared with echo results across groups usingchi square testing for dichotomous variables, and Wilcoxon 2-sam-ple rank test for continuous or multi-level variables.

Results. Expert's level of suspicion of heart disease was stronglyand positively associated with presence of disease (P<0.0001).

Clinical IM not on IM on diffl dx, but lessImpression diff'l dx likely than other dx

IM likelihood 26/389, 6.7% 44/176, 40.5%

IM most likely, IM the onlybut other dx considerationalso listed

116/144, 80.6% 143/155, 92.3%

Abbreviations: diff'l dx=differentialmurmur.

diagnosis; IM=innocent

Age of pt at presentation to cardiology clinic has strong negativeassociation with likelihood of heart disease (p<0.0001).

Patient age <0.10 years 0.10-1.00 years

IM likelihood 39/185, 21.1% 87/243, 35.8%

Patient age 1.00-4.00 years >4.00 years

IM likelihood 73/154, 47.4% 133/222, 59.9%

Among the 155 cases in which the experts' diff'l dx contained IM asthe sole consideration there were 12 in which heart disease wasdiscovered by echo. Four of these 12 have had catheter or surgicalintervention (atrioventricular septal defect repair-1, cor triatriatumrepair-1, secundum atrial septal defect repair-1, and patent ductusarteriosus coil-1). When IM was the sole consideration (n=155) and

the only stated reason for echo was pt, family, or referring physiciananxiety (n=43) there was only 1 case of heart disease discovered(2.3%). When symptoms, an abnormal electrocardiogram, or chestX-ray were among the considerations compelling the echo (n=112)11 cases of heart disease were discovered (9.8%); p<0.05.

Conclusions. Recognizing that in many cases IM is diagnosed clin-ically, conclusions drawn from this study are limited to those mur-murs in which diagnostic ambiguity remains after the expert clinicalexamination. In this context, the examiner's clinical impression oflikelihood of heart disease correlates well with presence of actualdisease. However, important disease is occasionally discovered evenwhen the expert formulates no plausible diagnosis except IM, espe-cially when reasons beyond family and referring physician anxietycompel the cardiologist to obtain an echo. Even when a murmursounds innocent to the expert examiner, clinical and laboratory cluessuggestive of heart disease should not be suppressed as indicationsfor echo in an effort to contain costs.

8SOMATIC GROWTH IN CHILDREN WITH SINGLEVENTRICLE.

Mitchell I. Cohen, MD1, David Bush, MD PhD', Robert J. FerryMD2, Thomas L. Spray, MD3, Thomas Moshang Jr., MD2, GilWernovsky, MD', Victoria L. Vetter, MD'. From the Divisions ofCardiology', Endocrinology2, and Cardiothoracic Surgery3 at TheChildren's Hospital of Philadelphia & The University of Pennsyl-vania School of Medicine, Philadelphia, PA.

Background: Growth failure occurs commonly with congenitalheart disease and may be related to congestive heart failure andhypoxia. Surgical repair of simple congenital heart lesions appearsto reverse the growth retardation. Surgical repair of complexsingle ventricle anatomy and/or physiology includes a stagedFontan operation to reduce the adverse effects of prolonged ven-tricular volume overload and hypoxemia. The impact of this ap-proach on somatic growth is unknown. The aim of this study wasdesigned to characterize the mid-term growth patterns in childrenmanaged initially with a hemi-Fontan followed by a modifiedFontan operation in early childhood.

Methods: Retrospectively, we reviewed the growth measure-ments of all children with single ventricle followed primarily atour institution who completed a staged Fontan operation between1/90-12/95. Growth measurements were available on all childrenprior to surgery and then annually for three years following theFontan operation. Growth data were obtained on siblings andparents for comparative purposes.

Results: During the study period 65 patients met eligibility cri-teria. The mean weight Z score was -1.49+1.12 at the hemi-Fontan operation. Weight gain improved by the Fontan(-0.91±0.99) and for the first two years following the Fontanoperation, but never normalized. The mean height Z score at thehemi-Fontan and Fontan operations were-0.67±1.14 and-0.89±1.18 respectively. Linear growth velocity continued to de-cline after the Fontan operation. At most recent follow-up (meanage 6.1±1.3 years; mean time from Fontan operation 4.4+ 1.4years), the mean height Z score was -1.15±1.2 and was signifi-cantly less than height Z scores for their parents and siblings. TheQp/Qs (pulmonary: systemic flow ratio) after the Fontan opera-tion was 0.95±0.2 and the most recent mean pulse oximetry re-cording was 94% (range 88-98%).

Conclusions: Despite near normal oxygen saturations and theabsence of congestive heart failure, children with single ventriclewho have been palliated with a Fontan operation are significantlyunderweight and shorter than the general population and theirsiblings.

654 SUPPLEMENT

0.5-

0-

-0.5 -

-1 -

-1.5 -

-2 -

U-, *

Height*

Weight El

Weight/ mBirth Hemi- Fontan Years Post Fontan Height

Fontan 1 3 5

9CARDIAC CONDUCTION IN MUTANTMICROPHTHALMIA MICE.

Colin T. Maguire, BS, David E. Fisher, MD, Charles I. Berul,MD, FAAP. Children's Hospital * Boston, Dana-Farber CancerInstitute, Harvard Medical School, Boston, MA

Background: The microphthalmia (Mi) gene encodes a helix-loop-helix transcription factor important in neural crest develop-ment. The Mi gene binds E box promoter/enhance element intarget genes and is subject to regulation via cytokine signalingpathways. Although Mi tissue expression is strikingly tissue re-stricted, it is found to be most abundantly expressed in cardiacmyocytes. However, as there is no obvious cardiac phenotype, thepurpose of this study is to determine whether Mi or related familymembers may modulate subtle features of cardiac development,such as regulation of electrical conduction.Methods: Surface 12-lead ECG's were obtained on 19 homozy-

gous mutant Mi-deficient mice and matched littermate controls.Heart rate, rhythm, axis, and ECG intervals were compared be-tween the 2 groups.

Results: The mutant mice were significantly smaller (weight12 ± 4 grams vs. 20 ± 5 grams, p < 0.05). The mean heart rate inmutant mice was 484 ± 31 BPM, compared with 488 ± 48 inage-matched wild-type littermates. There were no significant dif-ferences in heart rate, rhythm, axis, or ECG intervals betweenhomozygous mutant and wild-type mice.

ECG Findings:PR QRS QT SCL

MutantMi 35 + 3ms 17 ± 3ms 62 + 7ms 124 + 32msWild-type 36 ± 3 ms 18 + 3 ms 60 + 12 ms 123 ± 48 ms

Conclusion: The lack of measurable conduction defects in thesemice suggests several possibilities. The Mi factor may not regulatecardiac conduction, or might be compensated for by other HLHfamily members or other transcription factors. There may be moresubtle defects in cardiac conduction, not appreciable on surfaceECG. Conduction delay may become more manifest with provo-cation using programmed electrical stimulation, ion channel mod-ulating drugs, experimental ischemia, or electrolyte disturbances.Mi and associated factors may altematively regulate differentaspects of cardiac physiology or development, possibilities cur-rently under investigation.

10PROGRESSIVE ATRIOVENTRICULAR CONDUCTIONBLOCK IN A MOUSE MYOTONIC DYSTROPHY MODEL.

Charles I. Berul, MD, FAAP, Colin T. Maguire, BS, Josef Gehr-mann, MD, Sita Reddy, PhD. Children's Hospital * Boston, Har-vard Medical School, Boston, MA and University of SouthemCalifornia, Los Angeles, CA.

Background: Myotonic dystrophy (DM) is caused by expansionof a CTG trinucleotide repeat on human chromosome 19, andleads to progressive atrioventricular conduction disturbances.

Haploinsufficiency of DMPK, DMAHP and/or titration of RNAbinding proteins by expanded CUG sequences likely underlie thecardiac defects observed in DM. The purpose of this study was todetermine whether developmental progression of A-V block oc-curs in a mouse model of DMPK-deficiency.

Methods: Surface ECGs and intracardiac electrophysiology (EP)studies were performed in immature and adult DMPK-/-,DMPK'/- mice and wild-type (WT) DMPK+/+ controls. The RR,PR, QRS, and QT intervals were measured on ECG. Sinus noderecovery time, AV refractory periods, paced AV Wenckebach and2:1 block cycle lengths, atrial and ventricular effective refractoryperiods were compared between genotypes and age groups.

Results: There were no differences in ECG intervals or EP find-ings in the young mutant mice, but progressive PR prolongationin older mice.

so

5o

40

30

210

la

1-2 mo 46mo 12-15 mo 18-21 mo

The A-V conduction defects are also sensitive to DMPK genedosage. Adult DMPK-'- mice develop 10, 2° and 3° A-V block,whereas DMPK+'- mice develop only 10 heart block. Conclusion:These data demonstrate that developmental age as well as DMPKdose are critical factors modulating cardiac conduction and linkDMPK haploinsufficiency with cardiac disease in myotonic dys-trophy.

11ENDOTHELIN-1 BLOCKADE WITH BOSENTANDECREASES POST-REOXYGENATION VENTRICULARDYSFUNCTION AND LEUKOCYTE-MEDIATED INJURY

Jeffrey M. Pearl, M.D., Donald W. Thomas, C.CP., Jerri L. Mc-Namara, C.C.P., Jenni L. Raake, R.R.T., David P. Nelson, MD,PhD. Children's Hospital Medical Center, Cincinnati, Ohio

Background: Reoxygenation of hypoxic myocardium during re-pair of congenital heart defects results in leukocyte-mediated in-jury and poor ventricular function. Endothelin-1 (ET-1) which isincreased under conditions of hypoxia is a potent vasoconstrictor,directly depresses myocardial function, and stimulates leukocyteadhesion and activation. In order to determine if ET-1 blockadeimproves post-reoxygenation ventricular function and decreasesleukocyte-mediated injury neonatal piglets were studied.

Methods: Following instrumentation and baseline measure-ments, 14 open-chest piglets underwent 90 minutes of ventilatorhypoxia (FI02=.12), one hour of reoxygenation on cardiopulmo-nary bypass, and two hours of recovery (Group 1). An additional9 animals undergoing an identical protocol received an infusion ofBosentan (5mg/kg/hr) during hypoxia and reoxygenation (Group2). Systolic ventricular function (+dp/dt) was determined. LVmyocardium was analyzed at end-recovery for myeloperoxidase(MPO) activity and lipid peroxidase activity (LPO).

Results: In Group 1, RV dp/dt increased to 148% of baseline (533vs. 369) during hypoxia, but fell to 78% of baseline followingreoxygenation (281 vs. 360, p<.05). LV dp/dt decreased to 80% ofbaseline by end-hypoxia (994 vs. 1242, p<.05) and followingreoxygenation decreased to 52% of baseline (646 vs. 1242, p<.005).In contrast, Group 2 animals had complete preservation of RVdp/dt (102% of baseline) at end-recovery. In Group 2, LV dp/dtwas significantly less depressed at end-recovery than in Group 1(74% of baseline). LV dp/dt at end-recovery was significantlygreater (p<.05) in Group 2 than in Group 1 (903 vs. 646). Group 2had significantly lower (p<.05) myocardial tissue MPO than

1R DMPK+/+

*DMPK+I1-DMPK-/-.

SUPPLEMENT 655

Group 1; LV MPO in mU/50 mg tissue was 80.9 in group 1, 21.7in Group 2, and 13.1 in control hearts. LV LPO in nM/100 mg wettissue was also significantly lower in Group 2 (p<.05) than inGroup 1 at end-recovery; 4.6 in Group 1, 3.5 in Group 2, and 3.0 incontrol hearts. Conclusions: Reoxygenation of hypoxic myocar-dium results in leukocyte-mediated injury and decreased ventric-ular function. Increased levels of ET-1 during hypoxia may con-tribute to reoxygenation injury. ET-1 blockade with Bosentandecreases myocardial leukocyte activity as evidenced by lowerMPO and LPO values. This decrease in leukocyte mediated reoxy-genation injury may account for the improved functional recoveryseen with Bosentan.

12MITOCHONDRIAL CARDIOMYOPATHY: SPECIFICENZYMATIC AND DNA DEFECTS.

Jose Marin-Garcia*, MD, FAAP, Radha Ananthakrishnan* PhD.,Michael J. Goldenthal*, PhD, Mary Ella Pierpontt, MD, PhD.The Molecular Cardiology Institute*, Highland Park, NJ, Depart-ment of Pediatricst, U. Minnesota, Minneapolis, MN

Background: In a group of 30 children (ranging in age from 2weeks to 18 years) presenting with end-stage cardiomyopathy, 25(19 with DCM, 6 with HCM) manifested cardiac mitochondrialenzymatic defects. In this study we sought to establish the molec-ular basis for the enzymatic abnormalities using combined molec-ular and biochemical analyses.

Methods: Biopsied endomyocardial tissues were analyzed todetermine specific cardiac respiratory enzyme activity levels, mi-tochondrial DNA (mtDNA) levels, large-scale deletions and pointmutations in mtDNA by DNA sequence analysis.

Results: In this patient group, specific activity levels of car-diac mitochondrial respiratory enzymes were significantly re-duced compared to age-matched controls. Decreased activitylevels were found in complex I (n=9), III (n= 13), IV (n= 11) andV (n=9) but not in complex II, the only entirely nuclear-en-coded respiratory complex. Sequence analysis of cardiacmtDNA showed that 4 of the patients harbored novel hetero-plasmic mtDNA mutations in cytb (15508), tRNAARG(10424),tRNAALA(5655), ND4L (10554) and ND5 (14969); mutations inmtDNA-encoded structural proteins (cytb, ND4L, ND5) residedin highly conserved amino acid residues while the tRNA mu-tations were present in highly conserved nucleotides. A fifthpatient exhibited a heteroplasmic mutation in cytb (15236)which has been previously reported in association with mito-chondrial cardiomyopathy (MCM). None of these potentiallypathogenic mutations were present in controls (n=6) or incardiomyopathic patients with no enzymatic defect (n=5). Inaddition, 2 patients exhibited marked reduction in cardiacmtDNA levels. While specific mtDNA deletions were detectedin 7 patients, they were found in low proportion compared towild-type mtDNA levels (< 0.1%) and no relationship could beestablished between the levels of specific mtDNA deletions andenzyme activities.

Conclusions: In summary, specific mitochondrial enzymaticabnormalities are frequently present and heterogenous in chil-dren with both DCM and HCM. The basis for the respiratoryenzyme abnormalities can be explained in a subset of ourpatients as a result of either pathogenic mtDNA mutation ormtDNA depletion. These patients harboring both DNA andenzymatic defects fulfill a rigorous criteria defining mitochon-drial cardiomyopathy. Further study is underway to define themolecular basis for the observed respiratory enzyme defects inthe remaining patients as involving defective nuclear DNA loci.

13WHAT IS THE YIELD OF ECHOCARDIOGRAPHY IN THEEVALUATION OF SYNCOPE?

Saskia Ritter MD, LuAnn Minich, MD, FAAP, Richard Wil-liams, MD, FAAP, Susan Etheridge, MD, FAAP, Janet Craig,PNP, Lloyd Tani, MD, FAAP Department of Pediatrics, Univer-sity of Utah, Salt Lake City, Utah

Background: Syncope is common in children and most causesare benign. Studies published in 1995 suggest that routine echo-cardiography is not useful in the evaluation of adults with syn-cope. Similar studies have not been reported for children and therole of echo in the evaluation of childhood syncope remains con-troversial.

Purpose: The purposes of this study were to determine the yieldof echocardiography and to define any changes in its use for theevaluation of children with syncope over a 6 year period.

Methods: The cardiology data base was searched for all patients(pts) presenting with syncope between 1/93 and 1/99. Pts withpreviously diagnosed cardiac disease who subsequently devel-oped syncope were excluded. The medical records were reviewedfor patient demographics, year of presentation, physical exam,cardiac tests ordered and their results, and final diagnosis. Echoabnormalities were obtained by reviewing reports and videotapes.

Results: The 480 pts (266 females) ranged in age from 1.5-18.0 yr(12.3 ± 3.7, mean ± SD) and weight from 10.3-113.6 kg (47.4 ±17.9). Final diagnoses included vasovagal syncope in 341, long QTsyndrome in 14, arrhythmias in 6, cardiomyopathy in 2, andnoncardiac causes in the remaining 117 pts. Echoes were per-formed in 322 pts (67%). Echocardiographic abnormalities weredetected in 11 of 230 pts (4.8%) with a normal exam and ECG, andin 26 of 92 pts (28.3%) with an abnormal exam or ECG. The 37abnormalities demonstrated by echo included 26 minor valveabnormalities, 7 hemodynamically insignificant shunt lesions, 2mildly decreased shortening fractions (25%, 27%), and 2 cardio-myopathies. Only the 2 cardiomyopathies (hypertrophic obstruc-tive cardiomyopathy, right ventricular dysplasia) were consideredto be potential causes of syncope, and in both cases the ECG wasmarkedly abnormal. There was no significant difference in thepercentage of echoes ordered before vs after the 1995 publishedstudies (60% vs 70%, p = 0.27).

Conclusions: In the absence of an abnormal physical exam orECG, echo adds little to the evaluation of syncope in children. Wespeculate that pediatricians and pediatric cardiologists continueits routine use because of the paucity of data regarding the valueof echo in evaluating pediatric syncope. This pediatric studyshows a low yield of echo and should discourage its routine usefor the evaluation of syncope.

14CARDIAC EVENT MONITORING IN PEDIATRICPATIENTS

Marguerite M. Crawford, M.D., Howard P. Gutgesell, M.D.,F.A.A.P, Nancy L. McDaniel, M.D., F.A.A.P. Division of PediatricCardiology, University of Virginia Health Sciences Center, Char-lottesville, Virginia.

Background: Cardiac event monitors are frequently prescribedfor the evaluation of patients with complaints referable to thecardiovascular system. Studies on the use of these monitors inadults have found them to be efficacious for the evaluation ofpalpitations. The purpose of this study was to determine the useand results of cardiac event monitoring in children.

Methods: Retrospective chart review of 109 consecutive patientsseen in a tertiary care center pediatric cardiology clinic and issueda cardiac event monitor between 1995 and 1998.

Results: Ages ranged from 5 months to 32 years (mean 10.7 yrs)and 60% were females. Sixty-eight patients were healthy with

656 SUPPLEMENT

normal cardiovascular systems. Forty-one patients had underly-ing cardiac diagnoses including; suspected supraventriculartachycardia (SVT), Wolff Parkinson White syndrome, and 17 hadpreviously undergone cardiac surgery for structural heart abnor-malities. Indications for monitoring included complaints of: fastheart rate (78%), chest pain (54%) and syncope or presyncope(43%). Some patients had multiple complaints. Standard non-looping cardiac event monitors were issued to 107 patients for 30days. Two patients under 3 years of age were issued continuousloop event recorders. Six patients were given a monitor for morethan one month. The number of events recorded by each patientranged from 0 to 28, with the majority (58%) recording between 1and 3 events. Recordings in 100 patients (92%) demonstratednegative findings with normal sinus rhythm (35%), sinus arrhyth-mia (31%) or sinus tachycardia (26%). Nine patients (8%) hadpositive findings. Seven of these patients had at least 1 episode ofSVT. Of these 7 patients, only 1 had newly diagnosed SVT. Twohad undergone prior electrophysiologic ablation of reentrant path-ways, and 4 had previously suspected SVT. The 2 other patientswith positive findings were found to have profound bradycardia.Ten additional patients were highly suspected to have arrhyth-mias despite negative findings on event recordings. Two of thesepatients were found to have non-sustained ventricular tachycardiaon 24 hour Holter monitor. One patient with pre-excitation onelectrocardiogram and symptoms highly suspicious for SVT had apositive electrophysiologic study. The remaining 7 patients sus-pected of having SVT were educated on techniques to terminatetachycardia and when to seek medical attention. Cardiac eventmonitors detected only 9 positive diagnoses out of 109 patients(8%), at a cost of $70,800 (118 months at $600).

Conclusion: Cardiac event monitoring of pediatric patients isunlikely to reveal a pathologic diagnosis except in children with aknown or previously treated arrhythmia. The majority of childrenwith palpitations, chest pain, or syncope will have a sinus rhythmat the time of their symptoms. However, the use of event monitorsmay be helpful to provide reassurance to children and their fam-ilies.

15IS AMIODARONE MORE HEPATOTOXIC IN PATIENTSWITH FONTAN OPERATION?

Mayte I. Figueroa, MD, and Seshadri Balaji, MRCP. Division ofPediatric Cardiology, Medical University of South Carolina,Charleston, SC.

Background: Amiodarone (Amio) is often used for atrial flutterafter the Fontan operation (FO). FO patients have elevated venouspressure and hepatic congestion. We sought to determine whetherAmio's hepatotoxicity is more pronounced in FO patients.

Methods: Between 1984 and 1997, 12 FO patients (age 8-26 yrs,median 16.9) and 18 non-Fontan (NF) patients (age 2-33 yrs,median 14) received Amio. In the NF group, 13 patients hadcongenital heart disease. Their arrhythmia diagnosis was ventric-ular tachycardia in 10, atrial flutter in 6, and supraventriculartachycardia in 2. Liver function tests (LFT) (ALT, GGT, bilirubin)were performed before starting Amio, and 6 monthly thereafter.Mean follow-up in the FO group was 37 mos (range 4 mos-8 yrs)and in the NF group 54 mos (range 7 mos-10 yrs).

Results:

ALT pre ALT post GGT pre GGT post

NF 28 + 22 29 + 10 32 + 25 39 + 30FO 26 + 15 43 + 23 102 ± 85 161 + 141p ns <0.05 <0.05 <0.05

Amio, 8 FO patients and 3 NF patients (all with repaired tetralogyof Fallot and right ventricular dilatation) had elevated LFT.

Conclusion: 1) Amio causes significant hepatotoxicity in FOpatients; 2) LFT abnormalities are uncommon in NF patients,except after TOF repair with right ventricular dilatation; 3) Amioshould be used with caution in these two groups of patients withregular monitoring of LFT.

16AMIODARONE IS SAFE AND HIGHLY EFFECTIVE ASPRIMARY THERAPY FOR TACHYCARDIA IN INFANCY

Susan P. Etheridge, MD, FAAP, Janet Craig, PNP, University ofUtah and Primary Children's Medical Center, Salt Lake City, UT

Background: Amiodarone is effective for life-threatening ar-rhythmias. Frequent side effect have limited its use as initialtherapy, yet it may succeed where other antiarrhythmics fail. Wefound amiodarone alone or with propranolol to safe and effectivefor treatment of tachycardia in infancy.

Methods: Between 6/94-present, 44 infants (age 1 ± 1 mo,mean ± SD) with tachycardia were treated with amiodarone (19pts) or amiodarone and propranolol (25 pts). Diagnoses were: AVreentry tachycardia (AVRT)-26, AV node reentry tachycardia-4,atrial ectopic tachycardia (AET)-6, multifocal atrial tachycardia(MAT)-1, permanent form of junctional reciprocating tachycardia(PJRT)-4, and incisional atrial reentry tachycardia (IART)-3. Diag-nosis was made by ECG and/or esophageal EP study. At presen-tation, 14 pts had mild CHF and 5 were in shock. On initialechocardiogram, 8 (18%) pts had congenital heart disease 14 (32%)had decreased ventricular function. All patients underwent oralamiodarone load. Propranolol (1-2 mg/kg) was added if tachy-cardia continued after 4-5 days. Baseline and follow-up ECG, T4,TSH, and ALT were performed.

Results: Amiodarone loading and maintenance doses were 14 ±5 mg/kg and 7 ± 2 mg/kg, respectively. Pts were on telemetry for8 ± 2 days during loading and no proarrhythmias noted. All ptshad tachycardia control with amiodarone + / - propranolol. Atdischarge, all pts were asymptomatic with normal ventricularfunction. Forty pts (91%) were in sinus rhythm without tachycar-dia, and 4 pts (PJRT-1, AET-2, MAT-1) had occasional episodes ofasymptomatic tachycardia. Based on history, ECG and Holtermonitoring, all pts were free of tachycardia within 2 mo. of dis-charge. Pts were followed for 16 ± 14 mo. The baseline QTc was430 ± 30 ms and the maximal QTc on amiodarone was 466 ± 30ms. This increase was not statistically significant, but 27/44 (61%)had a QTc > 450 at some time during therapy. Typically the QTcincreased during loading and retumed to normal during mainte-nance therapy. Torsades de pointes did not occur. There was noincrease in ALT or T4. The average TSH increased during therapy(3.8 ± 2.8 vs 4.8 ± 2.2) but remained within the normal range in allpts. No side effects necessitated drug withdrawal. Propranolol hasbeen discontinued in 14/25 (56%) pts after 6 ± 4 mo. and amio-darone discontinued in 31/44 (70%) pts after 9 ± 7 mo. withouttachycardia recurrence. Thirty pts (68%) that have been followedfor > 9 mo. Medication is still needed in 8/30 (27%) (AET-2,PJRT-1, MAT-1, AVRT-4) in whom discontinuation of medicationresulted in tachycardia recurrence.

Conclusions: Amiodarone +/- propranolol is safe and highlyeffective for tachycardia control even in infants with difficult tocontrol arrhythmias such as PJRT, IART, and AET. Althoughfrequent side effects have been reported, none occurred in our pts.Although an initial hospitalization may be necessary, pts may besafely discharged once tachycardia is controlled. Medications canoften be discontinued after 9 mo. of therapy.

SUPPLEMENT 657

Bilirubin levels were similar in the two groups. Elevated LFTswere noted pre-Amio in 6 FO patients and 1 NF patient. Post-

17DIAGNOSTIC ACCURACY OF THE SCREENINGELECTROCARDIOGRAM IN GENOTYPED LONG QTSYNDROME.

Misha D. Miller, BA, Co-burn J. Porter, MD*, Michael J. Acker-man, MD, PhD., FAAP* Mayo Medical School; *Department ofPediatric and Adolescent Medicine, Section of Pediatric Cardiol-ogy, Mayo Foundation/Mayo Clinic Rochester, Rochester, MN.

Background: Inherited long QT syndrome (LQTS) may presentwith syncope, seizures, and/or sudden death due to ventriculartachyarrhythmias. Identification of at-risk family members whohave the genetic substrate for LQTS is critical.

Methods: Molecular testing of the 23 family members for theKVLQT1 mutation and symptomatic status facilitated the classifi-cation of each family member into the following patient groups; 13noncarriers, 5 asymptomatic carriers, and 5 symptomatic carriers.Each individual had a standard 12-lead electrocardiogram fromwhich the computer and manual (lead II) QTc, the maximum QTc,and the QT dispersion (QTd = maximum QT-minimum QT,irrespective of lead) were determined. Additionally, we deter-mined the accuracy of the computer ECG diagnostic interpretationfor each patient group.

Results: The computer generated QTc, when using a diagnosticcut-off of QTc 2 460 ms, demonstrated a positive and negativepredictive value of 100% for identifying those with LQTS. Despitethis complete separation of noncarriers from carriers, the auto-mated ECG diagnostic interpretation erroneously classified 6 of 23family members. Moreover, the interpretive statement, "normalECG", was ascribed for 50% of the family members proven to havethe ion channel defect. Although the maximum QTc was signifi-cantly longer for carriers than for noncarriers, there was consid-erable overlap between patient subsets. QT dispersion failed todistinguish LQTS individuals from noncarriers.

Conclusion: Reliance on the ECG interpretation will fail to iden-tify many at-risk family members. Careful consideration of theQTc with adherence to the QTc cut-off value of 460 ms must begiven independent of the ECG interpretive statements. It is sug-gested that all first-degree relatives of an identified LQTS probandhave a 12-lead ECG that is independently reviewed by a cardiol-ogist familiar with LQTS in an effort to improve screening for thispotentially lethal syndrome.

18PEDIATRIC SYNCOPE: COMPARISON OF EMERGENCYDEPARTMENT AND CARDIOLOGY CLINIC EVALUATIONPRACTICES.

Venkat Ramesh, MD, Tammy S. Wieand, MS, Ronn E. Tanel,MD, Mitchell I. Cohen, MD, Victoria L Vetter, MD, Larry A.Rhodes, MD, The Children's Hospital of Philadelphia, Philadel-phia, PASyncope can be an alarming symptom that often results in exten-sive diagnostic testing and hospitalization in pediatric patients.The purpose of this study is to compare the evaluation of patientswho are self-referred to an emergency department (ED) vs thosewho are seen by appointment in a cardiology clinic (CC).

Methods: A retrospective search was performed on a pediatricelectrocardiogram (ECG) database (1991-1998) for the test indica-tion of syncope. Patients with known congenital heart diseasewere excluded (n= 19). All ECGs, echocardiograms (ECHO), 24 hrHolter monitors, head up tilt tests (HUTT) and follow-up CC visitsfor each patient were reviewed.

Results: There were 620 patients (age lm to 18y) identified witha similar evaluation site distribution (ED, n=286; CC, n=315).There was no significant difference in age or gender between sites.Despite the equal proportion of abnormal ECGs, additional testswere performed more frequently in CC (p<0.05)(Table). Holters

were ordered more frequently than ECHO or HUTT, but abnor-mal results for all tests occurred with similar incidence at bothsites. There were more frequent abnormalities in Holters andHUTT. Pre-excitation was diagnosed in 3 patients (all CC). Pro-longed QT interval incidence was similar (ED, 5.2%; CC, 5.1%).Four hemodynamically insignificant structural lesions were iden-tified (ED, 2; CC, 2). Follow up was less likely when seen in ED(19% vs 44%) (p<0.05).

Abn EKG Echo

Total Abn

ED (n = 286) 118 (41%) 27 (9%) 2 (7%)CC (n = 315) 123 (39%) 77* (24%) 7(9%)

Holter HUTT

Total Abn Total Abn

49 (17%) 30 (61%) 12 (4%) 7(58%)164* (52%) 123 (75%) 85* (27%) 53 (62%)

* p < 0.05 between ED and CC.

Conclusions: Non-invasive tests were performed less often forpatients presenting with syncope to ED. Since abnormal test re-sults were of similar incidence in the 2 groups, some patientsevaluated in ED may have unrecognized abnormalities. Patientsseen in ED for syncope may need more aggressive follow-up.

19THE EARLY PROFILE OF MYOCARDIAL DYSFUNCTIONIN CHICKEN EMBRYOS AFTER NEURAL CRESTABLATION.

Hong Jin, MD, Margaret Kirby, PhD., and Linda Leatherbury,MD, FAAP. Department of Pediatrics, IMMAG DevelopmentalBiology, Medical College of Georgia, Augusta, GA.

Background: Ablation of premigratory cardiac neural crestcauses not only high incidence of persistent truncus arteriosus andaortic arch anomalies (interrupted aorta) but also myocardial dys-function in early cardiovascular development prior to the timethat neural crest cells would normally migrate into the heart andfar before the time when cardiovascular defects are seen. Wehypothesized that complete ablation of the cardiac neural crestwould induce more severely depressed contractility than partialablation; furthermore, we desired to identify the earliest develop-ment stage with myocardial dysfunction. Knowing this stagewould help us focus on how the migrating cardiac neural crestcells are important for myocardial function before reaching theheart.

Methods: Complete ablation of the premigratory neural crestfrom the otic placode to somite 3, or partial ablation to somite 2, atstage 9 produced the experimental chick embryo groups. Usingnormal-control chick embryos with the eggshell opened just priorto filming and sham-operated control embryos that were pro-cessed in parallel with experimental embryos, depressed contrac-tility and abnormal configuration of the heart tube were rated atstage 14. Using high-speed microcinephotography, end-systolicand end-diastolic dimensions of the outflow segment ventriclewere measured at stages 16 and 18 to assess cardiac performance.Pathological evaluation was performed at mature stage 28.

Results: Depressed cardiac contractility with abnormal configu-ration of the heart tube in embryos with complete neural crestablation was observed as early as stage 14. By stage 16, decreasedcontractility presented as decreased ejection fraction, increasedend-systolic residual volume, but without ventricular dilation.However, the depressed contractility progressed by stage 18, andwas compensated by ventricular dilation to maintain normalstroke volume, therefore, adequate cardiac output for survival.

658 SUPPLEMENT

Partial neural crest ablation caused less severely depressed con-tractility at stage 16, but similar cardiac dysfunction as completeablation by stage 18.

Conclusion: After complete cardiac neural crest cell ablation,myocardial dysfunction occurs earlier and is more severe. Inter-estingly, partial neural crest ablation only causes a difference inthe timing, not in the extent of the observed cardiac dysfunction,when compared with complete ablation. This study shows that thecardiac neural crest cells are essential for normal myocardial func-tion before they reach the heart at a stage when they should bemigrating through the pharyngeal arches around the aortic archarteries. There may be some specific modulating factors of thecardiac neural crest cells responsible for myocardial function,which is not necessarily associated with subsequent developmentof specific cardiac structural defects.

20A PROSPECTIVE ANALYSIS OF THE IMMUNOGENICITYOF CRYOPRESERVED NON-VALVED ALLOGRAFTS USEDIN PEDIATRIC CARDIAC SURGERY.

John P. Breinholt BS, John A. Hawkins MD, Linda M. LambertBS, Thomas C. Fuller Ph.D., Tracie Profaizer, Robert E. ShaddyMD. Depts of Pediatrics, Surgery, and Pathology, Primary Chil-dren's Medical Center and the University of Utah, Salt Lake City,UT.

Background: We have previously reported that cryopreservedvalved allografts used to repair congenital heart defects induce asignificant human leukocyte antigen (HLA) humoral antibodyresponse that broadens in reactivity within 3 months of surgeryand persists beyond 1 year. The purpose of this study was toprospectively determine the immunogenicity of non-valved allo-graft tissue used in the repair of congenital heart disease.Methods: We prospectively analyzed the immune response of 6

children, age 2 months to 10 years, who required a non-valvedallograft patch to alleviate stenosis during repair of a congenitalcardiac defect. The diagnoses in these patients were: Transpositionin 2 patients, aortic arch obstruction in 3 patients, and pulmonaryatresia in 1 patient. Non-valved allografts were required in 2patients to repair or reconstruct the pulmonary artery, in 3 torelieve the obstructed aortic arch, and in 1 patient to reconstructthe right ventricular outflow tract. In 6 cases, pulmonary arterialgrafts were used; in 1 patient, a section of glutaraldehyde-pre-served allograft pericardium was used. All patients received leu-kocyte filtered and irradiated blood products perioperatively toprevent sensitization against blood donor products. We prospec-tively measured the level of HLA panel-reactive antibody (PRA)prior to surgery, 1 week after, 1 month after, and 3 months afterallograft placement. PRA was determined in 2 ways: using theantiglobulin cytotoxicity technique against an HLA-select frozenT-lymphocyte panel and by flow cytometry using a pool of HLAClass I and II purified antigen coupled to latex beads. PRA isexpressed as the percentage of lymphocyte panel members (anti-globulin technique) or fluorescent positive beads (flow cytometry)against which the patient's sera react.

Results: In the 5 patients who received pulmonary allograft tissue,PRA measurements were 3.2 ± 5.6 % preoperatively and 0.0 % at oneweek after surgery. However, within one month, all patients showeda vigorous immune response. The measured PRA increased to 52.4 ±19 % at 37.8 ± 8 days after surgery, and further increased to 78.4 ±26 % at 3.2 ± 0.4 months after surgery. Flow cytometry demonstratedboth HLA Class I and Class II antibodies. At one month, Class I PRAincreased to 67 + 38 % and Class II was 52 ± 43 %. By 3 months,Class I and Class II PRA increased to 85 ± 31% and 58 ± 31%,respectively. In the patient who received the pericardial allograft,there was no increase in PRA in the first month, and only a minimalincrease in the PRA level to 5 % by 3 months.

Conclusions: Similar to valved allografts, cryopreserved non-valvedallografts induce a strong HLA antibody response that broadens in

reactivity within 3 months. This response represents antibody to bothHLA Class I and Class II antigens. This suggests that even smallpieces of cryopreserved non-valved allograft tissue exhibit sufficientimmunogenicity to induce a strong antibody response that could bedamaging to the tissue. The fact that the one patient in this study whoreceived glutaraldehyde-preserved allograft pericardium demon-strated no immune response warrants further investigation.

21IN VIVO ELECTROPHYSIOLOGY STUDIES INENDOTHELIAL NITRIC OXIDE SYNTHASE (eNOS)DEFICIENT MICE.

Amit Rakhit, MD, Colin T. Maguire, BS, Josef Gehrmann, MD,Ralph A. Kelly, MD, Thomas Michel, MD, PhD, Charles I. Bedl,MD, FAAP. Children's Hospital - Boston, Brigham & Women'sHospital, Harvard Medical School, Boston, MA.

Background: Nitric oxide has been implicated in the control ofautonomic function of the heart. There are three known isoformsof nitric oxide synthase expressed in varying cell types withcardiac myocytes expressing the endothelial isoform of the en-zyme. Endothelial nitric oxide synthase (eNOS) has been shown tomediate the attenuation of the L-type calcium channel and myo-cyte contractility by cholinergic and beta-adrenergic stimulation.Arrhythmogenic aftercontractions have been found in ouabain-treated isolated myocytes from eNOS-deficient mice though therehave been no similar in vivo studies on the role of eNOS inarrhythmogenesis.

Methods: In vivo cardiac electrophysiology studies (EPS) wereperformed in 10 mice completely lacking the eNOS gene(eNOS-/-) and wild-type (eNOS'++) littermate control mice. Base-line conduction intervals (RR, PR, QRS, and QTc) were measuredfrom surface ECG recordings and then intracardiac EPS testingwas performed. Cycle length (SCL), sinus node recovery time(SNRT, cSNRT), AV and ventricular refractory periods (AVERP,VERP) and paced AV and VA Wenckebach cycle lengths(AVWCL, VAWCL) were measured. Subsequently, VERP andVAWCL were remeasured after intracardiac isoproterenol admin-istration.

Results: Data analysis by Pearson t-test revealed no significantdifferences in ECG intervals, cardiac conduction times, refractoryperiods, or susceptibility to inducible arrhythmia in eNOS-defi-cient mice versus wild-type controls.

EP data SCL cSNRT AVERP AVWCL VERP VAWCL(msec)

eNOS-/- 152 + 3 70 + 58 61 ± 12 77 ± 13 51 ± 3 105 + 10(n = 10)

eNOS+/+ 124 ± 7 88 + 83 60 + 4 75 + 4 50 + 5 110 + 2(n = 5)

t-test .07 .85 .89 .69 .50 .54(p-value)

Conclusion: Despite the modulation of ion channel physiology inthe heart, a transgenic eNOS deficiency mouse model does notpredispose to cardiac conduction disorders or arrhythmia vulner-ability. Potential abnormalities might be inducible in provocativeexperimental conditions.

22THE EMERGENCY CENTER VS THE COMPUTER: WHICHIS THE BETTER ELECTROCARDIOGRAPHER?

Christopher S. Snyder, MD, Richard A. Friedman, MD, FAAP,Arnold L. Fenrich, MD, FAAP, Kelly O'Reilly, MS, Scott Reeves,MD, Naomi J. Kertesz, MD, FAAP. Texas Children's Hospital /Baylor College of Medicine, Houston, TX.

SUPPLEMENT 659

Background: Electrocardiograms (ECG) are frequently orderedin the pediatric Emergency Center (EC). Pediatric cardiologists arenot immediately available to interpret these ECGs, thus patientmanagement often is guided by the EC physician (including se-nior residents) interpretation. Despite this, the ECG interpretiveskills of EC physicians and a commonly used computer program(Marquette electronics 12 SL software) has yet to be evaluatedformally. The purpose of this study is to compare the accuracy ofthe EC physician vs. computer generated interpretation.

Methods: Demographic sheets were prospectively distributedwith all ECGs performed on patients <22 years old in the EC, from11/97 to 10/98. The EC physicians were blinded to the computerinterpretation. The interpretations were then compared to thereference standard-interpretation by a pediatric electrophysiolo-gist (EP). Each individual diagnosis, as well as the ECG as a whole,was assigned to one of the following: class I-abnormalities of littlepotential clinical importance i.e. sinus arrhythmia, early repolar-ization; class II-abnormalities that require non-emergent cardiacevaluation, i.e. left axis deviation, LVH; class III-abnormalities thatrequire immediate cardiology consultation, i.e. prolonged QTc,VT. The results of all cardiology consultations were recorded.

Results: 293 ECGs with interpretations by all three groups (EC,computer, EP) were analyzed. Correct interpretations, reported aspercent of total were:

Percent Correct P Value

Computer ER

Individual Dx n = 534Class I Dx n 395 82% 67% <0.001Class II Dx n 125 73% 30% <0.001Class III Dx n = 14 14% 28% NS

Overall ECG n = 293Normal ECG n = 113 100% 100% NSClass I ECG n = 91 75% 36% <0.001Class II ECG n = 75 75% 36% <0.001Class III ECG n = 14 14% 28% NS

Of the 89 patients with a class II or III ECG diagnosis, 33 hadknown cardiovascular disease (CVD) and had no new cardiaccomplaints. Of the remaining 56 patients, 37 (66%) were evaluatedby a cardiologist for the first time. Of those, 9 patients were foundto have CVD: VSD(2), SVT(2), total anomalous pulmonary venousretum(1), ASD(1), cardiomyopathy(1), arteriovenous fistulae(1),and hypoplastic aortic arch(1). The most common (n=5) class IIIdiagnosis missed by both groups was prolonged QT, (all missedhad QTC>.47).

Conclusions: (1)The knowledge base upon which EC physiciansdepend on to interpret ECGs needs improvement. (2) The com-puter does a satisfactory job identifying class I and H abnormali-ties, but fails to identify most class III abnormalities. (3)There is a16-24% incidence of undiagnosed CVD in patients with either aclass II or III abnormality. In an EC setting, it is imperative thatclass II and HI ECGs be identified prior to patient discharge so thatfollow up can be arranged. We speculate that distributing thecomputer interpretation to EC physicians may decrease the num-ber of class I and H abnormalities missed.

23DOPPLER CHARACTERIZATION OF DORSAL AORTICBLOOD FLOW IN THE MOUSE EMBRYO: INSIGHTS INTOTHE EARLY DEVELOPING CIRCULATION.

Colin K. Phoon, MD, FAAP, Orlando Aristizabal, PhD, andDaniel H. Turnbull, PhD. Pediatric Cardiology Program andSkirball Institute of Biomolecular Medicine, New York UniversitySchool of Medicine, New York, NY.

Background. Recent innovations in ultrasonic imaging now al-low noninvasive assessment of the developing embryonic circu-lation. In addition to high-resolution 40 MHz ultrasonic backscat-ter microscopy (UBM) providing 2-D imaging, we have developedUBM image-guided 45 MHz pulsed-wave (PW) Doppler capabil-ities. We sought to characterize dorsal aortic (DAo) blood flow andthus, cardiovascular hemodynamics, in the early mouse embryo.

Methods. 56 Swiss-Webster mouse embryos were studied in situbetween embryonic day (E) 9.5-14.5 in anesthetized dams. Rectaltemperature was closely maintained at 37±10 C. DAo angle as-sessed by UBM and Doppler interrogation from multiple viewswere used to maximize the velocity signal. The range-specific PWDoppler allowed insonation of DAo separate from intracardiac orumbilical signals. Doppler signals were converted by short-timeFourier transform into a spectral display on a LabView datamanagement program.

Results. Heart rate (HR) increased from 178±20 [SD] bpm at E9.5to 265±42 bpm at E14.5 (r=0.96, p<0.002, by linear regressionanalysis). Peak arterial velocity (PAV) increased from 46.5±16.3mm/sec at E9.5 to 161.3±37.8 mm/sec at E14.5 (r=0.96, p<0.002).Arterial velocity time integrals (VTI) also increased, from 4.0±1.7mm at E9.5 to 11.7±2.5 mm at E14.5 (r=0.94, p<0.006). Ejectiontime as a proportion of cycle length (ET/CL) also increased withgestation, from 0.357±0.042 at E9.5 to 0.467±0.043 at E14.5(r=0.90, p<0.02). Acceleration time (AT), an angle-and load-inde-pendent arterial Doppler index of cardiac contractility (Pediatr Res1991; 30:375), did not change with gestation (p=0.190). However,within each embryonic stage from E11.5-E14.5, AT correlated neg-atively and highly with HR (r< -0.82, p<0.025). Thus, any cor-rection for the increasing HR would result in a relative increase inAT as gestation progresses.

Conclusions. We have developed a PW Doppler system capableof measuring low-velocity blood flow in the early mouse embryononinvasively. HR was faster than described in invasive studies.Increasing PAV, VTI, and ET/CL indicate age-dependent in-creases in stroke volume (SV). Thus, cardiac output (HR x SV)increases dramatically from E9.5-E14.5. This increase in cardiacoutput is not likely attributable to changes in contractility, sincecardiac contractility appears to decrease from E9.5-E14.5 if HRchanges are taken into account. Increasing PAV and VTI indicatethat flow increases out of proportion to the increase in DAocross-sectional area, so that blood pressure must also increasefrom E9.5-E14.5. These quantifiable changes in the developingembryo not only provide insight into normal mammalian cardio-vascular development but also form the basis for the future studyof transgenic mice with aberrant cardiovascular development.

24COMPARISON OF HOLTER RESULTS ORDERED BYPEDIATRIC CARDIOLOGISTS VERSUS PEDIATRICIANSIN PATIENTS WITHOUT KNOWN HEART DISEASE.

Elise M. Riddle, MD, Naomi J. Kertesz, MD, FAAP, Arnold L.Fenrich, MD, FAAP, Richard Friedman, MD, FAAP. Baylor Col-lege of Medicine, Texas Children's Hospital, Houston, TX.

Background: Both pediatric cardiologists (CARD) and pediatri-cians (PED) commonly utilize the Holter monitor as a screeningtool for arrhythmias in patients without a known cardiac diagno-sis. The purpose of our study was to (1) determine the effective-ness of the use of Holter monitoring as a screening tool in patientswithout known cardiac disease or arrhythmias and (2) compareHolter results ordered by a CARD vs. a PED.

Methods: We retrospectively analyzed all Holters performed be-tween 1/98 and 1/99 on patients < 21 years of age without a knowncardiac diagnosis. Data obtained induded patient demographics,Holter result, and indication for Holter. Holters were divided into 2groups: Group 1-ordered by a PED, Group 2-ordered by a CARD.These groups were sub-divided further based on Holter result asfollows: normal, abnormal without clinical significance, and abnor-

660 SUPPLEMENT

mal with clinical significance. Occasional or frequent PAC's, occa-sional uniform or rare multiform PVC's, and rare ventricular cou-plets were classified as abnormal without clinical significance.Frequent PVC's/ventricular couplets, accelerated ventricular or junc-tional rhythm, and supraventricular, ventricular, or atrial ectopictachycardia were classified as abnormal with clinical significance.Rare events were defined as '10/hr; occasional events, 11-30/hr;and frequent events, > than 30/hr.

Results: 349 Holters met inclusion criteria, of which CARD ordered141, and PED ordered 208.

NORM ABN w/o SIG ABN w/SIG

CARD n = 141 77(55%) 17 (12%) 47(33%)PED n = 208 170 (82%) 19 (9%) 19 (9%)

Of the Holters ordered by CARD, 33% had clinically significantabnormal results and 45% had any abnormality vs. 9% and 18%ordered by PED, respectively (p<0.001, p<0.001). The totalamount spent by CARD to find each clinically significant abnor-mal Holter was $1665 per clinically significant abnormal Holter vs.the total amount spent by PED, $6076 per clinically significantabnormal Holter. The cost of an initial CARD clinic visit is 55%less than the cost of a Holter. Of the patients who had Holtersordered by PED, 38 without clinically significant abnormalities ornormal results were still referred to a CARD, of which 37 werediagnosed as normal and discharged from clinic. 6 patients withclinically significant abnormalities were not referred to a CARD.The presenting symptom with the highest yield of clinically sig-nificant abnormalities was ectopy/irregularity.

Conclusions: Holters ordered by CARD were 5 times more likelyto identify clinically significant abnormalities than Holters or-dered by PED. CARD spent a total of $4411 less per clinicallysignificant abnormal Holter than PED. Ectopy/irregularity wasthe presenting symptom with the highest yield of clinically sig-nificant abnormal results. For the initial evaluation of patientswith suspected cardiac disease, referral to a pediatric cardiologistis expected to be more cost effective than a Holter.

25LACK OF ELECTROPHYSIOLOGIC PHENOTYPE INIMMATURE FAMILIAL HYPERTROPHICCARDIOMYOPATHY MICE.

Laura M. Bevilacqua, MD, Colin T. Maguire, Josef Gehrmann,MD, Christine E. Seidman, MD, Jonathan G. Seidman, PhD,Charles I. Berul, MD, FAAP. Children's Hospital, Boston,Howard Hughes Medical Institutions, Harvard Medical School,Boston, MA

Background: The mechanisms underlying arrhythmia vulnera-bility and sudden death in childhood familial hypertrophic car-diomyopathy (FHC) are undefined. A mouse model of FHC re-sulting from an a-myosin heavy chain mutation (Arg403Gln) hasbeen a model of the electrophysiologic phenotype of this disease.The purpose of this study was to determine whether arrhythmiainducibility is related to histopathology, is developmentally pro-gressive, or is primarily inherent and independent of myocardialtissue abnormalities.

Methods: In vivo cardiac electrophysiology studies and surfaceECGs were performed in young and adult FHC mice and wild-typecontrols to investigate age-related differences in intracardiac conduc-tion parameters and arrhythmia inducibility. Atrial and ventricularpacing electrodes were placed by either a transvenous or epicardialapproach. Standard pacing and extrastimulus protocols were fol-lowed. The RR, PR, QRS, and QT intervals were measured from ECGleads. Variables measured during electrophysiology study includedsinus node recovery time, atrial and ventricular conduction proper-ties and refractoriness, and arrhythmia inducibility.

Results: There were no significant differences in surface ECG pa-rameters, SNRT, or atrioventricular refractory periods betweenyoung and adult mice in either the FHC or WT groups. There was asignificant difference in arrhythmia inducibility between young andadult FHC mice (33% of young mice vs. 52% of adult mice).

Conclusion: Age-related increases in histopathology correlate withincreased arrhyfthmia vulnerability in mice harboring the Arg4O3Ginmutation. Measurable cardiac conduction parameters show no intrin-sic age-related electrophysiologic abnormalities to account for theincreased incidence of VT in adult FHC mice. Young FHC mice arenot especially susceptible to ventricular arrhythmias, which maytherefore be secondary to histopathologic changes or developmen-tally progressive vulnerability.

26COACTATION INDEX: A NOVEL APPROACH TOIDENTIFY AORTIC ARCH OBSTRUCTION IN INFANTSWITH HYPOPLASTIC LEFT HEART SYNDROME AFTERTHE NORWOOD PROCEDURE.

Matthew S. Lemler, MD, FAAP, Thomas M. Zellers, MD, FAAP,Katherine A Harris, RDCS, Claudio Ramaciotti, MD. Depart-ment of Pediatrics, University of Texas Southwestern MedicalSchool, Dallas Tx.

Background: Recurrent aortic arch obstruction has been identi-fied as a complication of the Norwood procedure in infants withhypoplastic left heart syndrome. Doppler echocardiography iswidely used in the diagnosis of routine aortic coarctation. Assess-ment of potential aortic arch obstruction after the Norwood pro-cedure by routine measures is complicated by the unique physi-ology caused by the presence of a modified Blalock-Taussig shunt.Previous studies using routine echocardiographic measurementshave yielded only 73% sensitivity and 92% specificity. This studywas undertaken to evaluate the accuracy of a coarctation indexand to compare this index to both routine echocardiographicmeasurements and to the clinical exam in the diagnosis of coarc-tation in infants status post Norwood procedure.

Methods: The following echocardiographic measurements wereobtained retrospectively: 1) coarctation index (CI) (defined as theratio of the narrowest portion of the descending aorta to the distalthoracic descending aorta); 2) peak instantaneous gradient in thedescending aorta (DDA); 3) presence of an abnormal abdominalaorta flow pattern (DAA); 4) presence of moderate to severe rightventricular dysfunction (RVD); and 5) presence of moderate tosevere tricuspid regurgitation (TR). Additionally each patient'sclinic note was reviewed to determine if a coarctation was sus-pected by a pulse difference on physical exam (PD). The perfor-mance of an intervention to relieve an arch obstruction defined thepresence of a coarctation.

Results: Twenty-one patients were evaluated. The median age atcatheterization was 4.5 months. The median time interval betweenechocardiogram and catheterization was 7.0 days. Ten patients(47%) were diagnosed with coarctation. None of the infants in ourstudy demonstrated the classic flow pattern of coarctation (flowthrough systole and diastole). Including the 10 patients with aorticarch obstruction. The table below describes the results of eachvariable in correctly predicting coarctation.

p- Sensitivity Specificity Pos. Neg.value Pred. Pred.

Val Val

CI < .7 .0001* 91% 100% 100% 90%DDA > 30 .0237* 64% 90% 88% 69%DAA .9999 45% 60% 56% 50%RVD .4789 18% 100% 100% 50%TR .9999 27% 30% 50% 53%PD .1486 36% 90% 83% 60%

SUPPLEMENT 661

Conclusions: Only the coarctation index < .7 and a descendingaorta Doppler gradient > 30mmHg accurately predicted the pres-ence of a coarctation. The coarctation index was more sensitiveand specific than the Doppler gradient. Typical Doppler flowpatterns or the presence of a pulse difference on physical examcannot be relied on to diagnose the presence of coarctation ininfants status post the Norwood procedure.

27CONVERSION OF ATRIOPULMONARY OR LATERALATRIAL TUNNEL CAVOPULMONARY ANASTOMOSIS TOEXTRACARDIAC CONDUIT CAVOPULMONARYANASTOMOSIS

J.A.M. van Son, MD, F.W. Mohr, MD, J. Hambsch, MD, P.Schneider, MD, G.S. Haas, MD Herzzentrum, University ofLeipzig, Leipzig, Germany

Background: Patients with an atriopulmonary (AP) Fontan con-nection and enlarged right atrium or obstructed lateral atrial tun-nel (LAT) Fontan connection may have complications of atrialdysrhythmia, thromboembolism, right pulmonary vein obstruc-tion, and protein losing enteropathy. Conversion of these Fontanconnections to an extracardiac conduit (EC) cavopulmonary anas-tomosis may improve central systemic venous flow patterns andprovide clinical improvement.

Methods: Eighteen patients (7 to 40 years old) with AP anasto-mosis (n= 15) or obstructed LAT (n=3) presented at 5.7 ± 3.9 yearswith severe right atrial dilation (n= 15), Fontan pathway obstruc-tion (n=12), atrial dysrhythmia (n=13), pleural effusion (n=8),right atrial thrombus (n=3), right pulmonary vein obstruction(n=3), and protein losing enteropathy (PLE)(n=3). All patientsunderwent conversion to an EC cavopulmonary anastomosis.

Results: Two patients with PLE died on the 30th and 52ndpostoperative days secondary to persistent PLE. At a mean fol-low-up of 19 months, the remaining 16 patients had marked(n= 11) or moderate (n=5) clinical improvement. In the 13 surviv-ing patients with previous AP anastomosis there was a drasticreduction in right atrial size. Four of 13 patients with atrial dys-rhythmias converted to sinus rhythm. The right pulmonary veinobstruction as present in 3 patients resolved after conversion.

Conclusion: Conversion to an EC cavopulmonary connection inpatients with AP or LAT Fontan connection associated with ob-struction, right atrial enlargement, atrial dysrhythmia, or atrialthrombus may lead to clinical improvement. The conversion op-eration should not be unduly delayed to prevent the developmentof irreversible rhythm disturbances or PLE. The advantage of theconversion operation may be questionable in patients with PLE.

28IMPACT OF INITIAL PALLIATION ON OUTCOME INPATIENTS WITH PULMONARY ATRESIA AND INTACTVENTRICULAR SEPTUM: A TWO INSTITUTION STUDY

Cathryn S. Finch, MD, Zahid Amin, MD, James M. Berry,RDMS, William B. Strong, MD, John L. Bass, MD, Holland V.Moore, MD and John E. Foker, MD Department of Pediatrics,Medical College of Gerogia, Augusta, and University of Minne-sota, Minneapolis.

Background: Pulmonary atresia with intact ventricular septum(PA/IVS) is a deceptively simple term for a complex anomaly. Themanagement is usually based on the size of the tricuspid valve(TV) and right ventricle (RV), and the presence of RV dependentcoronary circulation (RVDCC). Our bias has been that the eventualoutcome of PA/IVS (biventricular repair or Fontan operation) isdependent on the initial operation and not on the size of TV or RVif there is no RVDCC.

Methods: From 1986 to 1998, 34 patients were admitted with thediagnosis of PA/IVS. Patients with critical pulmonary stenosis

and Ebstein's anomaly were excluded. No patient was excludedbecause of small TV or RV size. Patients were divided into 3groups: Group A patients had an RV outflow patch alone (n=24),Group B patients had a systemic to pulmonary artery shunt alone(n=7), and Group C patients had other procedures (n=3). Echo-cardiograms were reviewed to measure the size of the TV and RVfrom an apical 4-chamber view. The clinical status of the patient atthe last follow up was reviewed.

Results: Cumulative mortality was 26%. Group A mortality ratewas 21% (5/24). Of the 19 survivors, 18 (95%) had a biventricularrepair. Group B mortality rate was 43% (3/7). Of the 4 survivors,1 (25%) had a biventricular repair. Group C mortality rate was33% (1/3), and 1 patient received biventricular repair. The TVZ-value ranged from -1 to -4.5 (mean -3.1) and the RV Z-valuefrom -3.8 to -11 (mean -6.9). There was no difference in TV orRV Z-values according to initial treatment group or eventualrepair (biventricular vs Fontan). Clinically, all patients are acya-notic and without signs of heart failure. Although the difference inthe mortality rate was not statistically significant (p=0.56), thelikelihood of receiving a biventricular repair was significantlygreater for Group A patients (p<0.001).

Conclusion: We conclude that the initial palliative procedure hasa significant effect on outcome of patients with PA/IVS. Patchaugmentation of the right ventricular outflow patch indepen-dently increases the chance of biventricular repair.

29PEDIATRIC CARDIAC SURGERY IN A LOW VOLUMEINSTITUTION: QUALITY ASSESSMENT.

Rodolfo Neirotti, MD, FETCS, Donald Malcolm, MD, DominicSanfilippo, MD, Donald Jones, DO, Gwendolyn Fosse, RN,BSN, Thomas Steffens, CCP DeVos Children's Hospital, GrandRapids, Michigan

Background: Studies have suggested that a critical volume isnecessary for good results in pediatric cardiac surgery. We re-viewed our experience as a low volume pediatric cardiac surgerycenter with one surgeon and appropriate cooperating disciplines,to assess quality as measured by morbidity and mortality out-comes.Method: 717 consecutive pediatric cardiac surgeries (463 open

and 254 closed heart procedures) performed between April 1993and January 1, 1999, were reviewed. Data reviewed includedpatient diagnosis, age at operation, weight, time to extubation,complications, survival to discharge, and average length of stay.Hospital charges were also reviewed. Patients with hypoplasticleft heart syndrome were referred elsewhere.

Results: 347 (49%) operations were done in the first year of life.151 operations were performed in the first month of life.

Procedure n Deaths Neonatal n DeathsProcedures(51 month)

Ductus arteriosus 129 0 Closed heart 119 2Coarctation of 49 1 Open heart 32 5

the aortaAtrial septal 119 0

defectVentricular septal 111 0

defectFontan 11 1Tetralogy of 65 0

FallotInterrupted aortic 6 0

archComplete AVSD 21 1Arterial switch 13 2Others 193 8Total 717 13 Total 151 7

662 SUPPLEMENT

62 premature infants having ligation of isolated ductus arteriosuswere excluded from the remainder of the analysis. Median agewas 22 months. Median weight was 13.16 kg. 81.5% of patientswere extubated within 6 hours postoperatively (76.2% in the op-erating room). 98.2% survived until discharge. Major complica-tions were: reoperation for bleeding (1), complete heart block (2),and renal (6). No major neurological complications occurred. Themean charges were $20,071 per hospital stay. In 1997 the averagestay from procedure to discharge was 4.5 days (patients < 12months averaged 5.72 days).

Conclusions: This experience encompassed a diversity of condi-tions in neonates and children. The population treated in our insti-tution had favorable outcomes as assessed by morbidity and mortal-ity as well as by length of stay and hospital costs. Key factors to thissuccess included development of an appropriate team and goodjudgment with complex or atypical cases in determining if surgeryshould be performed locally. The difficulties of maintaining a lowvolume pediatric cardiac surgery program and the need for a collab-orative relationship with a quatemary center are acknowledged.

30LATE RESULTS AFTER REPAIR OF COMPLETE A-VCANAL: 25-YEAR FOLLOW-UP.

Dearani JA, Puga FJ, Schaff HV, O'Leary PW, Driscoll DJ,Danielson GK. Mayo Clinic, Department of Cardiac Surgery,Rochester, MN.

Background: The objective of this study was to review the long-term outcome of repair of complete atrioventricular canal defect.Methods: Between April 1968 and November 1985,196 patientsunderwent biventricular repair of complete A-V canal (CAVC).Mean age of 82 males and 114 females was 4 yr (range, 27 days-34yr). Down's syndrome was present in 43%, and 20% of pt had aprior PA band. Preoperative mean Qp/Qs and PVR were 2.6(0.3-12.2) and 5.1 (0.2-17.8), respectively. Single patch repair wasperformed in 92% and double patch in 8%. Intermittent cross-clamp was utilized in 50%, crystalloid cardioplegia (CP) in 33%and blood CP in 17%. Cleft closure was standard and eccentricmitral annuloplasty was done in 10%.

Results: Overall operative mortality for this series extendingback to the early years of CAVC repair was 17%. Risk factors forearly mortality were younger age at operation (p=0.0001), failureto thrive preoperatively (P=0.007), longer bypass time (p=0.014)and heart failure preoperatively (p=0.03). Early postoperativemorbidity included prolonged ventilator support in 5%, bleedingin 3% and heart block in 2%. Follow-up was 95% complete amedian of 15 yr postoperatively (maximum, 28 yr). Actuarialsurvival at 5, 15 and 25 yr postoperatively was 92.6 ± 2.1%, 87.6 ±2.7% and 85.2 ± 3.5% respectively. The only risk factor for latemortality was a postoperative complication after initial repair(p=0.03). At late follow-up, 85% were in NYHA class I or II, and15% in class III; 52% were employed, 48% were students and 32%of non-Down's women had successful pregnancies. Reoperationoccurred in 17% of pt at a mean of 6.7 yr postoperatively (range 17d-20 yr). Reoperations included mitral valve replacement in 11%and mitral repair in 4%. The need for reoperation for MR usuallybecomes apparent within 5 yr of initial repair. Freedom fromreoperation at 5, 15 and 25 yr postoperatively was 90.2 + 2.4%,87.2 ± 2.8% and 77.6 + 4.7%, respectively. Risk factors for latereoperation were an early reoperation (p=0.006), any postopera-tive complication (p=0.01) and residual mitral regurgitation(MR)(p=0.01).

Conclusion: The intraoperative post-repair findings of significantMR should prompt further attempts at repair, late survival ap-pears favorable, and functional and social capacities of survivorsare excellent.

31RANDOMIZED, CONTROLLED TRIAL OF INHALEDNITRIC OXIDE FOLLOWING SURGERY FORCONGENITAL HEART DISEASE.

Ronald W. Day, MD, FAAP. University of Utah and PrimaryChildren's Medical Center, Salt Lake City, UT

Background: Inhaled nitric oxide selectively decreases pulmonaryvascular resistance in patients with pulmonary hypertension whohave not developed advanced pulmonary vascular disease. Thisstudy was performed to determine whether inhaled nitric oxideprevents pulmonary hypertensive crises following corrective surgeryor heart transplantation in patients with congenital heart disease.Methods: Patients with a systolic pulmonary arterial pressure

(sPAP) - 50% of the systolic systemic arterial pressure (sSAP)during the early postoperative period were randomized to re-ceive 20 parts per million inhaled nitric oxide or conventionaltherapy alone. Acute hemodynamic and blood gas measure-ments were performed at the time of enrollment and after aperiod of 1 hour. The effects of sustained therapy were moni-tored until patients were weaned from assisted ventilation andnitric oxide was also gradually withdrawn. The incidence ofpulmonary hypertensive crises was used to evaluate the effi-cacy of sustained therapy. A pulmonary hypertensive crisis wasdefined as an episode of suprasystemic pulmonary arterialpressure associated with an acute decrease in blood pressure,heart rate, or oxygenation which required a change in postop-erative care. Cross-over to inhaled nitric oxide was allowedonly for control patients who experienced a pulmonary hyper-tensive crisis.

Results: Significant improvements in heart rate, systolic pul-monary arterial pressure and oxygenation occurred after 1 hourof nitric oxide inhalation.

Nitric Oxide Group, Control Group,n= 19 n= 19

Baseline 1 hour Baseline 1 hour

Heart rate, min-1 163 ± 5 157 + 5* 160 ± 4 159 ± 4sPAP, mm Hg 51 ± 3 47 ± 2* 48 ± 2 49 ± 2sSAP, mm Hg 87 ± 5 86 ± 4 79 ± 2 82 ± 4PaO2/FIO2, mm Hg 131 ± 10 170 ± 15* 163 ± 23 180 ± 14

Mean ± SEM, * p < 0.05.

Three patients developed pulmonary hypertensive crises in eachgroup. In patients receiving inhaled nitric oxide, pulmonary hy-pertensive crises occurred only during attempts to manage pa-tients without neuromuscular blockade on the first postoperativeday. Pulmonary hypertensive crises did not recur in control pa-tients who failed conventional therapy and were subsequentlytreated with nitric oxide inhalation. A life-threatening episode ofpulmonary hypertension occurred in one control patient despitehyperventilation, sedation, neuromuscular blockade and in-creased inotropic support. This episode immediately resolved af-ter the onset of inhaled nitric oxide. The duration of inotropicsupport and assisted ventilation were not significantly decreasedby inhaled nitric oxide.

Conclusions: Nitric oxide acutely improves pulmonary hemody-namics and gas exchange following surgery for congenital heartdisease. Nitric oxide did not prevent pulmonary hypertensivecrises; thus, it is unlikely that this postoperative complication willbe significantly reduced by empirically treating all patients withpulmonary hypertension. However, a trial of therapy may bejustified when pulmonary hypertensive crises occur.

SUPPLEMENT 663

32INTRA-AORTIC BALLOON PUMPING IN INFANTS ANDCHILDREN: A TEN-YEAR EXPERIENCE.

John A. Hawkins, MD, L. LuAnn Minich, MD, FAAP, Lloyd Y.Tani, MD, FAAP, George M. Pantalos PhD, Gregory B. DiRusso, MD, Edwin C. McGough, MD, Depts of Peds and Sur-gery, Primary Children's Medical Center and University of Utah,Salt Lake City, UT.

Background: Despite widespread use of the intra-aortic balloonpump (IABP) in adults, its use in children remains limited. Thisstudy was undertaken to review our 10-year experience withpediatric IABP for left ventricular (LV) dysfunction and to evalu-ate the clinical use of echocardiography for IABP timing.

Methods: From June 1988 until January 1999, 22 infants and chil-dren underwent placement of an IABP for severe LV dysfunctionrefractory to medical therapy. The IABP was placed following repairof a congenital cardiac lesion in 13 patients and for LV failure frommedical reasons in 9 patients, including 5 patients listed for cardiactransplant. Ages ranged from 3 months to 17 years (mean=6+5.5 yrs)and weights ranged from 4.3 to 56 Kg (mean=19+14 Kg). Eightpatients were less than 3 years of age. Duration of IABP ranged from3 hours to 12 days (mean=6+5 days). The IABP was routinelyinserted through a prosthetic graft made of expanded polytetraf-louroethylene sewn to a longitudinal common femoral arteriotomy.Prior to 1994, IABP was timed using standard methods from the ECGand radial artery pressure waveforn. Since 1994, to avoid potentialsources of error, we have utilized M-mode trans-thoracic echocardi-ography to precisely time balloon inflation with aortic valve closureand balloon deflation with aortic valve opening.

Results: Overall, 13 patients survived hospitalization and are long-term survivors (13/22, 59%). Survival was improved with echocar-diographic timing (7/9, 78%) as compared to traditional timingmethods (6/13, 46%, p=0.20). Survival was also improved in thosechildren <3 years of age (6/8, 75%) as compared to those 3 years andover (7/14,50%/6, p=0.38). Survival was similar for IABP post-cardiot-omy (8/13, 62%) and medical patients (5/9, 55%). Three of the 4deaths in the medical group were in patients listed for transplantwho did not receive a donor heart. Complications occurred in 2patients, including sepsis in 1 patient awaiting transplant and tran-sient limb ischemia in 1 patient.

Conclusions: IABP is effective in small infants and children withcurrently available equipment and appears to be effective for mod-erate degrees of LV dysfunction in both medical as well as post-operative patients. Echocardiography is helpful in timing IABP in thepediatric population with rapid heart rates and only peripheral (rath-er than central) arterial pressure tracings. IABP in both infants andchildren approaches the success rate seen in adults when propertiming is used.

33DIFFERENCES IN INCIDENCE OF INFANT CONGENITALHEART PROCEDURES FROM A MULTICENTERCONSORTIUM.

Lee A. Pyles, FAAP, Stanley Einzig, William A. Neal, FAAP,James H. Moller, FAAP. University of Minnesota, Minneapolis,MN and West Virginia University, Morgantown, WV

Background: Infant congenital heart disease (CHD) requiring sur-gery remains a challenging problem. This study investigates theincidence of CHD in Arkansas (AR), Minnesota (MN), Missouri(MO) and West Virginia(WV), states for which the children withCHD are felt to be uniformly reported to the Pediatric Cardiac CareConsortium (PCCC). We hypothesized that an increased incidence ofcomplex CHD is seen in WV as compared to the other states.

Methods: All patients enrolled in the PCCC for the years 1991-1995from AR, MN,MO andWV were evaluated. A cohort of patients wasselected which included all AR, MN, MO and WV children bom of

resident mothers between 1991-1994 with primary cardiac surgery/interventional cath at less than 2 years of age. In this time period, livebirths were distributed as follows (see table):

State Live Births <2 yo CHD <2 yo/1000 HLHS

AR 139306 386 2.77 .100MN 261629 683 2.61 .160MO 303610 817 2.69 .155WV 87845 255 2.90 .205

AS/Coarct All Left Obstrt Abnl Situs Commn Ventricle

.316 .416 .151 .194

.317 .478 .076 .134

.342 .497 .076 .132

.421 .626 .114 .137

Results: Incidences of cardiac procedures were analyzed usingCox's F-test for comparison of rare events. WV infants showed anincidence of cardiac procedures 1.08 times the other 3 states.Infants from WV under age 2 were 1.32 times as likely to undergoprimary surgery or balloon procedure for left side obstructivelesion from 1991-1995 as AR, MN, MO children from the sametime period (p < 0.05) and 1.4 times as likely to undergo a HLHSprocedure (p < 0.05, 95% confidence limit 0.84-2.15). Incidence ofHLHS is 0.205/1000 live births in WV vs. avg. 0.146 for the other3 states. Other common ventricles were normally distributed (seetable) as were lesions such as TOF and CAVC (not shown). Ab-normalities of cardiac situs were 1.86 times more common in ARinfants vs. the other 3 states (p < 0.01, 95% confidence limit1.08-3.08). In the 4 states, rare lesions such as pulmonary sling(n=3), cor triatriatum (n=4), ALCAPA (n=8) and Ebstein malfor-mation (n=7) were also noted.

Conclusions: Careful analysis of differences in population-basedincidence of CHD procedures may yield clues to etiology of CHD.Variability may represent differences in detection or management.Resource allocation may need to reflect regional differences.

34INCIDENCE AND PREDICTORS OFSUPRADIAPHRAGMATIC SYSTEMIC VENOUSCOLLATERAL FORMATION FOLLOWING THE FONTANOPERATION.

Howard S. Weber, MD, FAAP, Steven Zangwill, MD, FAAP andStephen E. Cyran. MD, FAAP. Department of Pediatrics (Cardi-ology), Pennsylvania State University Children's Hospital, Her-shey, PA.

Background: The occurrence of systemic venous collaterals as apotential etiology for decreased pulmonary blood flow following aHemi-Fontan or Fontan type operation has been described althoughthe incidence and predictors have not been well delineated. Thesecollaterals typically originate above the diaphragm (supradiaphrag-matic) and are not present preoperatively. They may also be ex-tremely insignificant preoperatively and thus are not identified byroutine angiography. We sought to determine the occurrence ofsupradiaghragmatic systemic venous collaterals (SSVC) followingeither a Hemi-Fontan or Fontan type operation in those patients whowere proven preoperatively to have no SSVC.

Methods: Since 1983, 118 patients were identified as having under-gone a Hemi or modified Fontan type operation at our institution.Thirty nine patients had sufficient pre and postoperative hemody-namic and angiographic data for study inclusion. Variables exam-ined between those with and without SSVC included: diagnosis,pre-Fontan right atrial pressure, age @ surgery, type of surgery(Hemi or modified Fontan), time from surgery to followup cath, SVCpressure post, change in SVC pressure pre to post Fontan, transpul-monary gradient post Fontan, pulmonary vascular resistence, sys-

664 SUPPLEMENT

temic saturation, systemic blood flow and the presence of a fenestra-tion in those patients following a modified Fontan.

Results: Fifteen patients (38%) developed postoperative SSVC ofwhich 6 (40%) were large and resulted in decreased pulmonary bloodflow and systemic desaturation. The venous collaterals identifiedincluded: anterior cardinal vein to the coronary sinus (n=7), vesselsarising from the innominate vein to pulmonary venous atria (n=4)and unusual azygous or hemiazygous like structures (n=4). Twelvepatients underwent successful coil occlusion of the SSVC includingthe 6 patients with large SSVC who had a significant increase insystemic saturation post closure. In 3 patients, the SSVC were con-sidered insignificant and were not occluded. Systemic saturation waslower (84 +/- 6 vs 90 +/- 5%, p=.005) and systemic flow washigher (3.3 +/- 0.8 vs 2.6 +/- 0.7 l/min/M2, p=.006) in patientswith vs without SSVC. When only patients with large SSVC (N=6)were compared to all others (N=33) the transpulmonary gradientwas higher (7.3 + / - 2.6 vs 5.2 + / - 1.7 mmHg, p=.01) and systemicsaturation was lower (82 + /- 5 vs 89 +/-5 mmHg, p=.007).

Conclusions: When not evident preoperatively, SSVC develop inapproximately 1/3 of patients following a Hemi-Fontan or modifiedFontan type operation. Larger SSVC result in lower systemic satura-tions and are more likely to occur in those patients with largerpostoperative transpulmonary gradients following either a Hemi ormodified Fontan operation. The majority of the SSVC are of nohemodynamic significance, although the possibility of these collateralvessels enlarging and becoming more clinically significant with ex-tended followup remains a possibility.

35EXTRACARDIAC REPAIR OF COMPLEX UNROOFEDCORONARY SINUS

J.A.M. van Son, MD, G.S. Haas, MD, J. Hambsch, MD, F.W. Mohr,MD Herzzentrum, University of Leipzig, Leipzig, Germany

Background: Complex unroofed coronary sinus (CUCS) with apersistent left superior vena cava (SVC) has as its commonest majorassociated intracardiac anomaly a partial or complete atrioventricularcanal (AVC) defect. In this clinical setting, intraatrial baffle repair hasa reported mortality rate of as high as 50%. Based on this experience,we recently have strived for an extracardiac repair of the anomaloussystemic venous component with atrial septation in CUCS.Methods: In 2 young infants (aged 4 and 7 weeks) with CUCS,

bilateral SVCs, right isomerism, and complete AVC, in addition topatch closure of the ventricular component of the AVC, a baffle wasconstructed between the pulmonary veins and the mitral valve. In 4subsequent infants (aged 7, 10, 16, and 20 weeks) with CUCS, bilat-eral SVCs, complete AVC, right isomerism (n=3), and mild infun-dibular stenosis (n=1), repair consisted of end-to-side anastomosis ofthe left SVC to the right SVC and complete repair of the AVC andassociated conditions.

Results: There was no perioperative or late mortality. The earlypostoperative course in the 2 patients with intraatrial baffle wascharacterized by increased left atrial pressure (18 and 20 mm Hg),supraventricular tachycardia, and varying degrees of pulmonaryvenous congestion. At 10 weeks postoperatively, 1 of these patientswas successfully converted to a left SVC-to-right SVC anastomosisand septation of the atria. In the 4 patients with a primary leftSVC-to-right SVC anastomosis, the hemodynamic result was excel-lent with a median left atrial pressure of 11 mm Hg on the firstpostoperative day. At a median follow-up of 12 months, all 5 patientswith an extracardiac repair of CUCS are clinically well with widelypatent left SVC-to-right SVC anastomoses.

Conclusion: The extracardiac repair technique for CUCS, as op-posed to the intraatrial baffle repair, avoids creation of a small andlow-compliant left atrial compartment with the potential for devel-opment of pulmonary venous congestion.

36CLOSURE OF SINGLE AND MULTIPLE ATRIALCOMMUNICATIONS USING THE AMPLATZER SEPTALOCCLUDER.

Wolfgang A.K. Radtke, MD, B. Rush Waller, MD, Girish Shirali,MD, FAAP, Henry B. Wiles, MD, FAAP. Medical University ofSouth Carolina, Charleston, SC.

Background: Device occlusion of atrial communications is emerg-ing as an altemative to surgical closure. The 20-month, single insti-tution experience with the Amplatzer occluder is reported.

Methods: Sixty-four patients were considered for device occlusionof atrial communications between August 1997 and April 1999. In 14patients, transesophageal echocardiography showed insufficient rimaround the defect, inadequate size or previously unrecognized addi-tional lesions, and device placement was not attempted. Fifty pa-tients, aged 2-75 years (median 8.7 years) with body weights of9.8-113 kg (median 27.6 kg) and Qp/Qs of 0.7-4.8 (median 1.7),underwent device implantation. Eight patients had 2 or 3 defects.Defect size ranged from 2-21 mm. Six additional interventions wereperformed in 3 patients: 2 stent placements into right pulmonaryartery, 2 coil occlusions of modified Blalock-Taussig shunts, 1 pul-monary balloon valvuloplasty and 1 coil occlusion of a ductus arte-riosus.

Results: All attempts of device implantation were successful. De-vice size ranged from 4-32 mm (median 16 mm). Two occluderswere implanted in 5 patients. Implantation from the right internaljugular vein was performed in 4 patients. Procedure time rangedfrom 44-212 minutes (median of 124 min). Fluoroscopy time rangedfrom 9.4-38.4 min (median of 20.1 min). There were no deviceembolizations, and there were no other major complications. Atrialfibrillation occurred during diagnostic procedure and during place-ment of the device in 1 patient. The marker band detached from thedelivery sheath during retraction of the device in 1 patient, andembolized into a left pulmonary artery branch. Catheter retrieval wasunsuccessful and the marker band was left lodged in a posteriorsubsegmental pulmonary artery branch without obstruction andwithout sequelae. Forty-eight patients (96%) were discharged thefollowing day. Complete occlusion of the defect(s) was achieved in43/50 (86%) immediately after placement, in 44/50 (88%) at 24 hours,in 35/37 (95%) after 6 months, and in 16/17 (94%) after 1 year. Allresidual defects were less than 2.5 mm in diameter at the latestfollow-up. No late complications occurred during median follow-upof 6 months. All devices remained in proper and unchanged position.

Conclusion: Closure of atrial communications using the Amplatzerseptal occluder is safe and effective during early follow-up.

37FIVE-YEAR EXPERIENCE WITH COIL OCCLUSION OFPATENT DUCTUS ARTERIOSUS USING LONGGIANTURCO COILS WITH 4-6 LOOPS.

Wolfgang A.K. Radtke, MD. Medical University of South Caro-lina, Charleston, SC.

Background: Transcatheter occlusion of the patent ductus arte-riosus (PDA) has become standard treatment, but a controversypersists over the need for retractable or detachable coils to im-prove safety and efficacy. A 5-year consecutive, single-center ex-perience with nondetachable coils is reported.

Methods: Transcatheter PDA occlusion using Gianturco coilswas attempted and accomplished in 158 patients over a 5-yearperiod with a median age of 2.9 years (2 months to 58 years) anda median weight of 13.1 kg (3.3 to 90 kg). No patient with asmallest ductus diameter of less than 4.5 mm was excluded. Thesmallest ductus diameter ranged from 0.1-7.8 mm with a mean of1.8 mm. Attempts were always made to avoid coil protrusion intothe pulmonary artery or aorta by using proper coil size selection,repositioning by catheter or, if necessary, removal. Coils with 4-6

SUPPLEMENT 665

loops were placed if the size of the ductal ampulla permitted. Coilswere delivered without snare or forceps technique. Aortographywas performed 10 min after placement; color flow echocardiogra-phy was performed 2-12 hours and 6 months after placement.

Results: Coils with 4-6 loops were used in 90%. One to threecoils (mean 1.2) were implanted mostly transarterially. Medianfluoroscopy time was 12.4 min (4-37 min). Two inadvertent em-bolizations occurred to the pulmonary artery (1.3%). Pulse losswas observed in 3 patients (1.9%) and resolved under heparin orthrombolysis treatment. No significant left pulmonary artery oraortic arch stenoses were observed. Seventy-three percent of pa-tients were discharged the same day. Complete closure wasachieved in 82% (129/157) after 10 min, in 92% (144/157) after2-12 hours, and in 98% (121/124) after 6 months. Ductus type,patient age, weight or heparinization had no influence on occlu-sion rates. Larger ductus size was significantly associated withresidual shunt (p<0.0001). There were no late complications.

Conclusion: Transcatheter occlusion of the PDA using long Gi-anturco coils is safe and effective without detachment mechanism.

38THE USE OF TELEMEDICINE IN PATIENTS WITHPOSSIBLE CONGENITAL HEART DISEASE TO OPTIMIZECARE AND FACILITATE TRANSPORT.

Kenneth M Shaffer MD, Howard Heiman MD FAAP, JohnBrownlee MD FAAP, Herb Whitley MD FAAP. San AntonioMilitary Pediatric Center (SAMPC), Lackland AFB TX.

Background: Military pediatric medicine utilizes a system oftertiary care centers connected to numerous outlying facilities bya complex transport system. The purpose of this study is toevaluate the use of telemedicine for initial assessment in patientswith possible congenital heart disease (CHD) in order to instituteappropriate care and to triage for potential transport. Methods: Wecompleted a retrospective review of all cases of telemedicine car-diac evaluations (Tele-echo). All patients were evaluated usingreal-time telemedicine links with a pediatric cardiologist atSAMPC. Data collected included: patient demographics, diagno-sis, effect on transport plan, and institution of management basedon telemedicine findings. Ancillary studies (chest radiographs,electrocardiograms) were available for review on some, but notall, patients. Echocardiography with real-time imaging was sup-ported at the referring institution by ultrasonographers with vary-ing experience levels. A pediatric cardiologist completed a subse-quent confirmatory evaluation.

Results: From 20 May 1996 through 20 March 1999 there were 134potential neonatal transports to SAMPC. Twenty telemedicine eval-uations were completed. Seventeen patients were neonates (meanage = 1.8 days). Two patients were two months and one was fiveyears old. Final diagnoses included: normal cardiac anatomy (elevenpatients), pulmonary valve stenosis (PVS)(four patients), patent duc-tus arteriosus/possible coarctation of the aorta(CoA), ventricular sep-tal defect (VSD), partial atrioventricular canal (AVC) defect, an un-balanced AVC (small LV) and truncus arteriosus. There was oneincorrect diagnosis-possible PVS with a VSD was diagnosed in anormal heart. Sensitivity of Tele-echo = 100%, Specificity = 86%. Onseven of the twenty patients, the decision to not transport the patienton prostaglandin El was aided by Tele-echo findings. In fourteen ofthe twenty patients the mode of transport was influenced by theconsultation. One "normal" patient was transported by fixed-wingaircraft for non-cardiac reasons. Two additional patients with cardiacdisease were transported to SAMPC during the study period frominstitutions not connected via the telemedicine network.

Conclusion: Real-time telemedicine is an appropriate mechanism tofacilitate the triage of patients with possible congenital heart diseaseat distant institutions.

MODE OF TRANSPORT

Normal, n=1 1 4 oa Transport

\/SD, n=1.Personal Vehicl

pVS, n=4------

PDAIPoss CoANSD n=ii --- mbulanc

OcV Primum ASD, n

_--)Fixed-vAng Transporirruncus Arteriosus, n1| -F-

39CARDIAC TROPONIN I LEVELS IN PEDIATRIC PATIENTSWITH ACQUIRED HEART DISEASE.

Richard V. Williams, MD, FAAP, Timothy M. Olson, MD,FAAP, Paul C. Young, MD, FAAP and Robert E. Shaddy, MD,FAAP, Primary Children's Medical Center, University of Utah,Salt Lake City, UT.

Background: Cardiac Troponin I (cTnI) has recently been shownto be a sensitive and specific serum marker for myocardial injuryin adults with coronary artery disease. The utility of cTnI in theevaluation of pediatric acquired heart disease has not yet beenfully evaluated.

Methods: Beginning in July 1998 we obtained cTnI levels in allpatients presenting with depressed left ventricular (LV) functionand/or suspected acquired heart disease. Serum cTnI levels weremeasured using an Abbott AxSYM system. A serum cTnI >2 ng/mlwas considered abnormal. The charts and echocardiograms of allpatients in whom cTnI levels were obtained were reviewed. Onlypatients with structurally normal hearts were included in this study.

Results: Seventeen patients were included in this study. cTnI waselevated in 6 patients (11.5±10.5 ng/ml, range 2.9-31.8 ng/ml) withthe following diagnoses: CO toxicity (n=2), idiopathic hypocalcemia(n=l), septic shock (n=l), myocarditis (n=l), and transplant rejec-tion (n=l). cTnI was normal in 11 patients (0.7±0.5 ng/ml, range0.3-1.9 ng/ml) with the following diagnoses: acute Kawasaki diseasewith coronary artery involvement (n=4), idiopathic dilated cardio-myopathy (n=2), hypertensive cardiomyopathy (n=2), acute rheu-matic carditis (n=2) and camitine deficiency (n=l). In patients withelevated cTnI there was a significant correlation between cTnI andnumber of days requiring support with epinephrine (r=0.83,p=0.04). There was no difference in LV shortening fraction in pa-tients with normal and elevated cTnI (23±13% vs 15±11%, respec-tively, p=O.22), and no correlation between cTnI and LV shorteningfraction in patients with an elevated cTnI. In patients with depressedLV systolic function who had follow up echocardiograms, 4/4(100%) with elevated cTnI demonstrated improvement in LV func-tion and 3/5 (60%) with normal cTnI demonstrated improvement(p=0.44). All of the patients with Kawasaki disease and coronaryartery involvement had serum cTnI levels <0.4 ng/ml.

Conclusions: 1) Elevation of cTnI is common in pediatric patientswith some types of acquired heart disease. 2) cTnI levels may predictacute inotropic needs when elevated. 3) Elevations in cTnI are notpredictive of clinical outcome based on echocardiographic findings.4) cTnI is not elevated in patients with Kawasaki disease and coro-nary artery involvement.

40HEMODYNAMIC DISTURBANCES IN HUMAN FETUSESWITH OBSTRUCTIVE CONGENITAL HEART DISEASE.

Michael R. Brumund, MD, and William A. Lutin, MD, PhD,FAAP. Department of Pediatrics, Section of Pediatric Cardiology,Medical College of Georgia, Augusta, Georgia.

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-le

Background: The purpose of this study was to compare thebiventricular function in human fetuses with obstructive and non-obstructive congenital heart disease (CHD).

Methods: This was a retrospective case control study of 228 fetalechocardiograms from 151 pregnancies, 89 with CHD and 62matches healthy fetuses. Patients were classified as left (LVO) or rightventricular oufflow obstruction (RVO), atrial or ventricular shunts(AVS), other (0), or normal (NL). Left and right ventricular endsystolic (ESV) and diastolic volumes (EDV), stroke volume (SV), andejection fraction (EF) were measured using the modified Simpson'srule. All data are expressed in percent normal using matched normalcontrols from our laboratory. Patient group data were analyzed usinganalysis of variance.

Results: Of our patients fetal echocardiograms, 29 showed LVO, 31had RVO, 64 had AVS, and 95 had normal hearts. LV and RV EDVwere not significantly different in the NL and CHD fetuses. As agroup, the fetuses with CHD had significant elevations in LVESVand RVESV (217 and 207% respectively, p<0.0001). Patients withnon-obstructive lesions (AVS) had significantly higher LV andRVESV (195 and 205%, p<0.002) when compared to NL. The eleva-tions in ESV resulted in a 19% decrease in the LVSV, a 15% decreasein the RVSV (p<0.05), and significantly lower ejection fractions, seetable.

AVS (n) LVO (n) RVO (n) 0 (n)

LVSV (% NL) 79.5 (59) 53.9 (25) 85.9 (30) 83.5 (9)RVSV (% NL) 91.2 (57) 62.9 (25) 104.6 (30) 77.2 (9)

hi the LVO group, the LVESV and LVSV were more severely affectedthan in the RVO or AVS groups (p<0.05). In the RVO group, both LVand RVESV were significantly increased when compared to the AVSgroup (p<O.00l). LV and RVEF were similar in the NL fetuses (73and 70% respectively). Patients with LVO had lower LVEF (44%),than patients with RVO (52%), other lesions (55%), or AVS lesions(55%). The LVEF in the RVO, 0, and AVS groups were similar andsignificantly lower than NL. Conclusions: Fetuses with congenitalheart disease had diminished LV and RVEF and SV compared tofetuses with normal hearts. Fetuses with left or right heart oufflowobstruction had significant decreases in SV and EF when comparedto fetuses without obstruction.

41COURSE OF LEFT VENTRICULAR FUNCTION ANDDIMENSIONS BEFORE AND AFTER AORTIC VALVEREPLACEMENT FOR CHRONIC AORTICREGURGITATION.

Anne G. Farrell MD, Roger A. Hurwitz MD, FAAP and TimothyM. Cordes, MD Dept. of Pediatrics, Indiana University School ofMedicine, Indianapolis, IN

Background: In most adult patients with chronic severe aorticregurgitation (AR), left ventricular end-diastolic dimension(LVEDD) and left ventricular end-systolic dimension (LVESD)become severely dilated. Aortic valve replacement (AVR) re-sults in substantial decrease in left ventricular dilatation andimprovement of function, even within the first few months afteroperation. To better define these changes in the pediatric pop-ulation, we studied the effect of AVR on left ventricular dimen-sions and performance in pediatric and adolescent pts. withchronic AR.

Methods: Serial preoperative and postoperative left ventricularmeasurements were evaluated in 26 pts. who underwent AVR forchronic AR between August 1991 and October 1998. 2D-echocardio-graphic parastemal long axis views were used to determine LVEDD,LVESD, ejection fraction (EF) and fractional shortening (FS)

Results: (values are absolute, not indexed to BSA; p values c: 0.05are significant)

100

90

80

70

60

50

40

30

20

10

0

Time from surgery(yrs.)

100

-90

-80

,70

,60 'O50 n

40 030

20-EF

10LVEDD

0--_-FS

_4LVES D

Significant preoperative changes over time included increase inLVEDD (both initial to mid, and mid to late preoperative studies) andLVESD and decrease in EF and FS. Significant postoperative changesincluded an early decrease in LVEDD (to within normal range) andLVESD. Although not significantly changed postoperatively, EF andFS did have an increased trend towards preoperative values. Therewas no significant correlation between preoperative LVEDD andearly or late postoperative changes in EF (r =-0.31).

Conclusions:. Decreasing EF and FS accompany increasing LVEDDand LVESD prior to AVR and appear to progress with time. AfterAVR, early reduction of left ventricular dilatation appears to be themost substantial change seen in the pediatric population. There is nota significant improvement in ejection fraction, but the function is notabnormally low in pediatric pts. prior to AVR. Therefore, serialechocardiographic measurements can detect the early onset of leftventricular changes and help guide management of pts. with AR.When dilatation of the left ventricle is first noted, pts. may have a"window of opportunity" to optimize timing of AVR by resultsobtained from more frequent echocardiograms.

42CONTRAST ECHO DURING CARDIACCATHETERIZATION FOR THE DIAGNOSIS OFPULMONARY AVMS IN PATIENTS WITH FONTAN/HEMI-FONTAN CONNECTION.

Marcus S. Schamberger MD, Anne G. Farrell MD, Eric S. Eben-roth MD, Timothy M. Cordes MD, Robert K. Darragh MD,Sanjay R. Parikh MD. Dept. of Pediatrics, Indiana UniversitySchool of Medicine, Indianapolis, IN.

Background: Development of pulmonary arteriovenous malfor-mations (AVMs) in patients (pts) after construction of Hemi-Fontan connection is a known problem. Small pulmonary AVMs,however, are difficult to diagnose by pulmonary angiography.

Methods: 9 Hemi-Fontan pts and 3 Fontan pts (mean time aftersurgery: 1.52 ± 1.1 yrs) underwent elective cardiac catheterization(cath). Pulmonary artery and SVC angiograms were performed toassess for the presence of AVMs. Agitated saline was injected withthe catheter in identical positions and subxiphoid echo pictures ofthe left atrium (LA) were obtained. Appearance of more than atrace of micro-bubbles in the LA was considered positive forAVMs. In some saline injections, angiography showed a wedgedcatheter position. If bubbles appeared in LA, confirmatory SVCinjection was performed in those pts.

Results: Only 3 of the 12 pts (2 with Hemi-Fontan and 1 withFontan) showed clear angiographic evidence of pulmonaryAVMs. However, 6 of the 12 patients (including the 3 with positivefindings on angiography) had appearance of micro-bubbles in theLA after saline-contrast injections. Careful restudy of the 9 nega-tive angiograms was performed. Rapid clearance of contrast ma-terial from the pulmonary arterial phase with poor opacification of

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the capillary bed was noted in the 3 pts with positive bubbles inthe LA. This confirmed that AVMs were present but not appreci-ated on initial angiography.

Conclusions: Pulmonary artery and SVC injection of saline contrastunder echo during cardiac cath is highly sensitive for the presence ofpulmonary AVMs. Small AVMs may not be apparent on pulmonaryangiography in about 50% of patients. The development of theseAVMs may be partly responsible for increasing systemic arterialdesaturation often seen in these pts. Positive saline contrast studiesshould be confirmed by SVC injection to exclude false positive resultsdue to peripherally wedged catheter position.

43ECHOCARDIOGRAPHIC PREDICTORS OF RESTRICTIVEINTERATRIAL COMMUNICATION REQUIRING BALLOONATRIAL SEPTOSTOMY IN INFANTS WITH HYPOPLASTICLEFT HEART SYNDROME

Neda Mulla, MD, FAAP; Anne Osher, DVM; Lawrence Beeson,DrPH; Ranae Larsen, MD, FAAP. Loma Linda Children's Hospi-tal. Loma Linda, CA.

Background: Restrictive interatrial communication (IAC) is asignificant source of morbidity and mortality in infants with hy-poplastic left heart syndrome (HLHS). We have sought to identifyechocardiographic predictors of restrictive IAC requiring balloonatrial septostomy (BAS).

Methods: Serial echocardiograms of 44 infants presenting withHLHS were reviewed retrospectively. Infants were studied fromtime of admission to final end point of transplantation, Norwoodor death. BAS was performed in 17 infants for clinical indicationsof desaturation, increasing oxygen requirements and/or respira-tory distress. Data collected included age at echo-cardiographicstudies, age at BAS, age at end point, maximum velocity (Vmax),mean velocity and IAC area based on the width of the color flowjet across the IAC.

Results: Of 17 BAS infants, 11 (65%) were transplanted, one (6%)had Norwood and 5 (29%) died. Of 27 non-BAS infants, 17 (63%)were transplanted, 4 (15%) had Norwood and 6 (22%) died. Me-dian age at end point was greater for BAS infants at 50 (22-186)days vs. 15 (3-102) days for non-BAS (p=0.0001). Median age atBAS was 22, range 2-67 days, only three infants required BAS atage < 16 days. Initial study variables at mean age 7 ± 5 days werecompared for the two groups. Initial Vmax was greater for BASinfants 1.86 ± 0.34 vs. 1.54 ± 0.34 m/s (p=0.017). The graph showsthe relationship of age to Vmax for both groups. Vmax increasedwith age for both groups, but at a greater rate for BAS infants.Regression analysis for initial Vmax and age at end point yieldsp=0.05 and 0.007, respectively.

u

0

v

10 20 30 40 50

Mean Age (in days) at time of Echo

Conclusion: Initial maximum velocity through interatrial com-munication and longer interval to surgery or death are indepen-dent predictors of need for BAS.

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1999;104;648Pediatrics Larry Mahoney

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