e63Abstracts / Journal of Electrocardiology 44 (2011) e1–e64

Background: We have enforced the simple heart examination with a pocketsize event electrocardiogram (ECG) on that day of the marathon rally, forpredicting heart problem.Method: The examination corner was installed in the starting point of 5 bigmarathon rallies in Japan, and lead I of the ECG in CG-2100 pocket sizeevent ECG corresponding was recorded for 32 seconds for 2596 applicanttotal people (1558 men and 1038 women: ten 80 years old). The ECGspecialist made out the ECG later and classified it according to the severityof ECG findings.Results: It was classified from normality to abnormality into G0-G5according to the severity of ECG findings and as GN about noise withoutdiagnosis. The results were as follows: G0, 2,224 (85.7%); G1, 49 (1.9%);G2, 113 (4.4%); and G3, 7 (0.3%), and did not have G4 or G5. Moreover, thejudgment of GN was performed by 203 (7.7%). Content of abnormalfindings was 16 SVPC, 33 VPC, 19 AF, 1 A-V Brock, 7 negative T wave, 50RBBB, 1 LBBB, 2 WPW syndrome, and 9 ST-T abnormalities, and so on,were seen. The subject of being not able to make out the electrocardiogramwas drift and low voltage of lead I. In the marathon rally participant, a lot ofabnormal ECG such as atrial fibrillations and abnormal ST-T were seenmore than the expectation. A pocket size event ECG can inspect a lot ofECGs for easy way to use in short time. As for this ECG, it was confirmed tobe able to diagnose other abnormal findings, though it was especially usefulfor the diagnosis of arrhythmia. It was suggested for a noise and a lowpotential to improve it considerably as a record condition by the rerecord andother lead (II, etc).Conclusion: The simple method of inspection using the event electrocar-diograph was enforced to the applicant on the day when the citizensmarathon rally was held, and an abnormal findings were admitted to 169(6.5%) of 2596 people more than we expected. The pocket-size event ECGis useful as a lot of handy heart screening immediately before beginning ofthe marathon rally for the participant.

doi:10.1016/j.jelectrocard.2010.12.154

P75Equivalent dipole vector analysis for detecting pulmonaryhypertensionMatevz Harlandera,d, Barbara Salobira, Janez Toplisekb,Todd T. Schlegelc, Vito StarcdaDepartment of pulmonary diseases, University Medical Centre Ljubljana,SloveniabDepartment of cardiology, University Medical Centre Ljubljana, SloveniacNASA Johnson Space Center, Houston, TX, USAdInstitute of Physiology, Faculty of Medicine, University of Ljubljana,Slovenia

Background: Various 12-lead electrocardiogram (ECG) criteria have beenestablished to detect right ventricular hypertrophy as a marker of pulmonaryhypertension (PH). Although some criteria offer good specificity, they lacksensitivity because of a low prevalence of positive findings in the PHpopulation. We hypothesized that 3-dimensional equivalent dipole (ED)model could serve as a better detection tool of PH.Methods: We enrolled (1) 17 patients (12 female, 5 male, mean age 57 years,range 19-79 years) with echocardiographically detected PH (systolicpulmonary arterial pressure N35 mm Hg) and no significant left ventriculardisease, and (2) 19 healthy controls (7 female, 12 male, mean age 44, range31-53 years) with no known heart disease. In each subject, we recorded a 5-minute high-resolution 12-lead conventional ECG and constructed principalsignals using singular value decomposition. Assuming a standard thoraxdimension of an adult person with homogenous and isotropic distribution ofthorax conductance, we determined moving equivalent dipoles (ED),characterized by the 3D location in the thorax, dipolar strength, and thespatial orientation, in time intervals of 5 milliseconds. We used the sum ofall ED vectors in the second half of the QRS complex to derive the ampli-tude of the right-sided ED vector (RV), if the orientation of ED was to theright side of the thorax, and in the first half the QRS to derive the amplitude ofthe left-sided vector (LV), if the orientation was leftward. Finally, theparameter RV/LV ratio was determined over an average of 256 complexes.

Results: The groups differed in age and sex to some extent. There was anonsignificant trend toward higher RV in patients with PH (438 ± 284 units)than in controls (280 ± 140 units) (P = .066), but the overlap was such thatRV alone was not a good predictor of PH. On the other hand, the RV/LVratio was a better predictor of PH, with 11 (64.7%) of 17 of PH patients butonly in 1 (5.3%) of 19 control subjects having an RV/LV ratio greater than0.70 (P b .001).

Conclusion: The use of ED for evaluating PH shows good specificity at areasonable sensitivity. The results are limited due to the small study groupsand differences in age and sex, but further investigations are warranted,including ED's diagnostic accuracy for PH vs that of other proposed ECGand vectorcardiogram criteria.

doi:10.1016/j.jelectrocard.2010.12.155

P76Cardia-mediated bradycardia in the fetusParvin Dorostkar, Shanti SivanandamUniversity of Minnesota, Minneapolis, USA

Fetal cardiac arrhythmias have been recognized with increasing frequency.Fetal tachycardia is one of the most common causes of nonimmune fetalhydrops resulting in high fetal morbidity and mortality. The most significantfetal arrhythmias are supraventricular tachycardias, occurring at a rate of47% to 68%. Severe bradycardias, in contrast, account for approximately 5%of all fetal arrhythmias. Fetal bradycardia is diagnosed when the fetal heartrate is less than 100 beats/min and is usually associated with nonconductedpremature atrial contractions and less commonly with fetal heart block.When fetal heart block is immune mediated, the mortality is as high as 20%;therefore, an accurate diagnosis is imperative. We describe a unique cause offetal bradycardia where fetal “echo” beats were diagnosed by inferencesupporting a bradycardia, which should be self-limited, requiring notreatment. In 2 fetuses, bradycardia with a heart rate of 70 to 90 beats/minwas noted in association with a history of intermittent fetal supraventriculartachycardia. Careful echocardiographic evaluation of the heart rhythmrevealed retrograde pulmonary blood flow in a bigeminal fashion inassociation with nonconducted atrial extrasystoles. The diagnosis of blocked“echo” beats was contemplated. This diagnosis should be considered whenintermittent fetal tachycardia and bradycardia coexist, supporting coupledatrial extrasystoles causing bigeminal sinus node suppression, resulting inrelative bradycardia. The bradycardia rate is about half the rate of theunderlying sinus rhythm with eventual spontaneous resolution to sinusrhythm. The diagnoses of this tachycardia mediated bradycardia shouldprevent unnecessary therapy.

doi:10.1016/j.jelectrocard.2010.12.156

P77An open-source extensible software toolkit for forward and inverseproblems in electrocardiographyDana Brooksa, Burak Erema, Mike Steffenb, Jeroen Stinstrab,Robert MacLeodbaNortheastern University, Boston, USAbUniversity of Utah, USA

We introduce an extensible open-source software toolkit for forward andinverse problems in electrocardiography within the framework of theSCIRun package from the Center for Integrative Biomedical Computing.There is a dearth of such tools for the forward and inverse electrocardiogram(ECG) problems. By contrast, there are a number of well-known andfrequently used software packages, both academic and commercial, forsolving forward and inverse problems in brain source localization usingelectroencephalographic and magnetoencephalographic measurements. Theavailability of such packages has greatly aided progress in this field byfacilitating validation and fair comparison of algorithms and enhancing thescientific acceptance of new algorithms through increasing reproducibility

Table 1Correlation between T-wave magnitude and CMR measures

Comparison Group Pearson r P

IS vs T-wave magnitude All (n = 55) −0.16 .43LVEF vs T-wave magnitude All (n = 55) 0.35 .017LVEF vs IS All (n = 55) −0.66 b.0001IS vs T-wave magnitude Anterior (n = 17) −0.44 .08LVEF vs T-wave magnitude Anterior (n = 17) 0.69 .002LVEF vs IS Anterior (n = 17) −0.64 .006IS vs T-wave magnitude Inferior (n = 38) −0.40 .012LVEF vs T-wave magnitude Inferior (n = 38) 0.33 .043LVEF vs T-wave magnitude Inferior (n = 38) −0.59 b.0001

e64 Abstracts / Journal of Electrocardiology 44 (2011) e1–e64

of results. Our goal is for our toolkit to play a similar role in advancing theacceptance and utility of forward and inverse electrocardiography.We have designed our toolkit to allow flexibility in problem formulation andsolution approach by leveraging the dataflow network structure of SCIRun.This structure along with its built-in network editor provides flexible choiceof geometric model, equivalent source model, forward solution approach,and inverse solution method. In particular, the toolkit integrates access toepicardial and heart surface geometric models, activation-based (equivalentdipole layer) and surface potential–based source models, finite element andboundary element forward solutions, and a variety of standard and novelinverse algorithms. It exploits SCIRun interfaces to both ECGSim andMatlab, with easy incorporation of geometries, data, and forward modelsfrom the former and provided and user-designed algorithms written in thelatter. The toolkit leverages the ability of CIBC's BioMesh3d software tobuild multimaterial computational meshes from segmented image data, aswell as CIBC's Seg3D segmentation software, but can also readcomputational geometries produced outside the toolkit (including ECGSimgeometries). Because SCIRun gives easy access to critical algorithmparameters (which can also be passed to Matlab algorithms), the toolkitprovides interactive control of all aspects of the processing pipeline. Finally,the advanced visualization capabilities of both SCIRun and the CIBCvisualization software map3d allow the user to flexibly and rapidly examinemany aspects of the computational process and results.With support of the toolkit in both compiled and source code formats, variedinvestigators can compare algorithms and share data and eometries, thusfacilitating increased progress, confidence, and eventually clinical applica-tion of results in this field. Future versions will integrate other bioelectricmodeling capabilities such as defibrillation modeling and electricalimpedance tomography.

doi:10.1016/j.jelectrocard.2010.12.157

P78Relationship between T-wave magnitude and infarct size 3 monthsafter myocardial infarctionLoek Meijsa, Anton Gorgelsb, Sebastiaan Bekkersb, Charles Maynardd,Miguel Lemmertb, Galen WagnercaDepartment of Cardiology, Catharina Hospital, Eindhoven, The NetherlandsbMaastricht University Medical Center, Maastricht, The NetherlandscDuke University Medical Center, Durham, North Carolina, USAdUniversity of Washington, Seattle, Washington, USA

Background: The value of sequential T-wave changes on the electrocar-diogram (ECG) has less well been described in the follow-up of myocardialinfarction. We sought to investigate whether T-wave amplitude correlateswith infarct size (IS) and left ventricular ejection fraction (LVEF) measuredusing cardiac magnetic resonance imaging (CMR) 3 months afterreperfusion therapy.

Methods: Fifty-five patients with a first acute myocardial infarct referred forprimary percutaneous transluminal coronary angioplasty (PCI) were included.Electrocardiograms were analyzed within 4 hours after reperfusion and at 3months, measuring T-wave amplitudes of 2 contiguous infarct-related leads,summed up as 1 value called T-wave magnitude. Cardiac magnetic resonanceimaging was performed at 3-month follow-up. The correlations between T-wave magnitude, IS, and LVEF were tested with Pearson r correlationcoefficient. Subanalyses were performed using a 2-sample t test.

Results: A good correlation was found between LVEF and IS size (r = −0.7,P b .0001). Both in anterior (r = −0.44, P = .08) and in inferior infarcts (r =−0.40, P = .012), a positive correlation between infarct size and T-wavemagnitude was found at 3 months. The correlation between T-wavemagnitude and LVEF was 0.7 (P = .002) for anterior infarcts and 0.33 (P =.043) for inferior infarcts (Table 1). Both LVEF and IS were similar inpatients with and without an increase in T-wave magnitude after follow-up.

Conclusion:We found a strong correlation between IS and 3-month T-wavemagnitude. Three-month T-wave magnitude and LVEF correlate better in

anterior than in inferior MI. This could have clinical importance in thefollow-up of myocardial infarction patients treated with PCI.

doi:10.1016/j.jelectrocard.2010.12.158

P79Analysis of QRS slopes as a measure of depolarization changes duringacute myocardial ischemiaMichael Ringborna,b, Daniel Romeroc,d, Olle Pahlme, Galen S. Wagnerf,Pablo Lagunac,d, Esther Pueyoc,d, Pyotr PlatonovaaDepartment of Cardiology, Lund University, Lund, SwedenbThoracic Center, Blekingesjukhuset, Karlskrona, SwedencCommunications Technology Group, I3A, University of Zaragoza, SpaindCIBER de Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN),Zaragoza, SpaineDepartment of Clinical Physiology, Lund University, Lund, SwedenfDuke University Medical Center, Durham, NC

Background: Risk stratification of acute myocardial ischemia could beimproved by adding depolarization changes to the conventionally used ST-Tchanges. No QRS method has, however, reached clinical use yet .Weassessed the value of analyzing QRS slope changes to evaluate and quantifyischemia.Methods: In 79 patients undergoing prolonged elective percutaneouscoronary intervention (25 left anterior descending artery [LAD], 38 RCA,and 16 LCX occlusions), upward (US) and downward (DS) slopes of the Rwave, as well as upward slope of the S wave (TS) were determined atbaseline and continuously during the procedure among the 12 standard ECGleads. In 38 of the patients (8 LAD, 21 RCA, and 9 LCX), myocardialscintigraphic imaging was additionally performed during the occlusion andas a control the following day to quantify the ischemia.Results: For the total population (N = 79), DS changes were morepronounced than US changes in all leads but V1. In subgroup analysis, LADand RCA occlusions showed more pronounced changes of DS than US inanteriorly (V1-V5) and inferiorly (II, aVF, and III) oriented leads,respectively. For typical leads with S waves (V1-V3), TS showed equalamount of change as DS. The amount of DS change showed a clear spatialpattern, with LAD occlusions showing most changes in leads V2-V4; RCAocclusions in leads II, aVF, and III; and LCX occlusions in leads V5-V6. Inthe subgroup with scintigraphic imaging (n = 38), the sum of absolute,positive DS change among all leads displayed a significant correlation toboth extent and severity of ischemia (r = 0.70, P b .0001, and r = 0.73, P b.0001, respectively). The corresponding correlation between sum of R-waveamplitude increase among all leads, as well as QRS duration change andextent/severity, was r = 0.41, P = .011; r = 0.46, P = .004; r = 0.43, P =.007; and r = 0.48, P = .003, respectively.Conclusion: We conclude that analysis of QRS slopes offers a robustdepolarization parameter that could be used to evaluate myocardial ischemiain addition to conventional repolarization changes.

doi:10.1016/j.jelectrocard.2010.12.159