S Anatomical Obstacles to Catheter Ablation for

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62 The Official Journal of Korean Heart Rhythm Society

Introduction

Radiofrequency catheter ablation (RFCA) is

the first choice of treatment for symptomatic

AVNRT.1However,itsuseinpatientswithan-

atomicvariationscanbecomplicated.Here,we

presenttwocasesofcatheterablationforAVN-

RTinpatientswithanatomicvariations:anRA

septal diverticulum, and lung-disease-induced

heartdistortion,respectively.

Case1

A22-year-oldwomanpresentedwithpar-

oxysmal palpitation. Electrocardiography (ECG)

revealed narrowQRS tachycardiawith a pulse

rateof160beats/minduringpalpitation(Figure

1).Thepatient’sbloodpressurewas110/80mmHg

duringtachycardia.QRSrhythmwasregularand

pseudoR’wavewasobserved in theprecordial

leadfromV1toV3.Sinusrhythmwasrestored

following rapid administration of intravenous

adenosine(6mg).Thepatienthadnohistoryof

diseaseoroperations.Atransthoracicechocar-

diogram (TTE) showed normal left ventricular

ejectionfraction(60%)andnostructuralabnor-

malities.Forelectrophysiological(EP)investiga-

tion,a2-mmanda4-mmquadripolarcatheter

wereusedtorecordHisandrightventricular(RV)

activity, respectively. Unfortunately, placement

Received: May 23, 2014Revision Received: September 10, 2014accepted: September 14, 2014Correspondence: Sang Weon Park MD, PhD, Department of cardiology, Korea University Anam Hospital, 73, inchon-ro, Seongbuk-gu, Seoul 136-705, KoreaTel: +82-2-920-6394, Fax: +82-2-927-1478 E-mail: [email protected] Ko, MD, PhD, Division of cardiology

고려대학교 의과대학 내과학교실 노 승 영 / 박 상 원

Seung-Young Roh, MD / Sang Weon Park, MD, PhDDivision of Cardiology, Department of Internal Medicine, Korea University Medical Center, Seoul, Korea

Anatomical Obstacles to Catheter Ablation for Atrioventricular Nodal Reentrant Tachycardia

ABSTRACT

Atrioventricular nodal reentrant tachycardia (AVNRT) is one of the most common forms of arrhythmia. The first line of treatment is typically radiofrequency catheter ablation (RFCA), though the efficacy and safety of this procedure can be limited by anatomic variations. We present two cases of patients with anatomic variations undergoing RFCA for AVNRT. These variations were: first, a diverticulum in the right atrial (RA) septum, and second, heart distortion caused by a tuberculosis-destroyed lung. Despite efforts to normalize the procedure,

both variations complicated the execution of RFCA.

Key Words: ■ atrioventricular nodal reentrant tachycardia ■ catheter ablation ■ diverticulum ■ complication

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Figure 1. ECG for Case 1. The patient presented with palpitations. The observed narrow QRS tachycardia was attributed to AVNRT fol-lowing EP investigation. Pseudo R' was observed in precordial lead from V1 to V3 (arrows).

Figure 2. Right atrial angiogram for Case 1. A pouch-like structure with contractility was observed in the lower septum of the RA (indi-cated by dot line in A and arrows). It was not definitely separated in RAO view. (A) LAO view. (B) RAO view.a, duodecapolar catheter for RA; b, quadripolar catheter for His; c, quadripolar catheter for RV; d, pigtail catheter for dye injection

A B

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Figure 3. Coronary sinus angiogram by retrograde approach for Case 1. The pouch-like structure (indicated by arrows) in the right atrial septum was not enhanced.a, duodecapolar catheter for RA; b, quadripolar catheter for His; c, quadripolar catheter for RV; d, pigtail catheter for dye injection; e, Judkins catheter for left coronary angiogram *, coronary sinus ostium

Figure 4. ECG for Case 2. The patient presented with palpitation. The observed narrow QRS tachycardia was attributed to AVNRT fol-lowing EP investigation.

A B

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Figure 5. (A) Chest radiography for Case 2. The right lung was destroyed by prior tuberculosis infection. (B) Chest computed tomography for the same patient. The heart was rotated counter-clockwise and distorted by the destroyed lung.RV, right ventricle; LV, left ventricle; RA, right atrium

ofaduodecapolarcatheterintothecoronarysi-

nus(CS)failedasitcouldnotbeadvancedinto

theCSostium.Arightatrial(RA)angiogramwas

performed for structural analysis (Figure 2).A

pouch-likestructurewasobservedinthelower

septumoftheRA,neartheCSostium.Asthis

structureexhibitedcontractility,itwasdiagnosed

asadiverticulum,ratherthanaseptalaneurysm.

ACSangiogramrevealednoassociationbetween

thediverticulumandtheCS(Figure3).Attempts

toplacetheduodecapolarcatheterintheCSwere

impededbythediverticulum.AnEPstudywas

subsequently performed using a duodecapo-

lar catheter positioned at the RA. Tachycardia

wasinducedafteranatrio-His(AH)jump,and

atrioventricular and ventriculoatrial conduction

exhibiteddecrementalproperties.Clinicaltachy-

cardiawasattributedtoslow-fastAVNRTafter

differentialdiagnosticmaneuvers.Adeflectable

ablationcatheterwitha4-mmtipwaspositioned

at theanteriormarginof theCStoablate the

slowpathway.Theablationcatheterwasfound

tobeunstableyet itwaseasilymovedupand

downatthemarginoftheseptaldiverticulum.As

aresult,successfulRFCAwasonlyachievedafter

aconsiderabletimeinterval.

Case2

A71-year-oldmanwithatuberculosis-de-

stroyedlungpresentedwithpalpitationanddys-

pnea.Electrocardiography (ECG) revealednar-

row-QRStachycardiawithashortRP interval

andapulserateof170beats/minduringpalpita-

tion(Figure4).Thepatient’sbloodpressurewas

100/70mmHgatthetimeofrecording,andQRS

rhythmwasregular.Sinusrhythmwasrestored

followingrapidadministrationofintravenousad-

enosine(6mg).Thepatienthaddiabetesmel-

litus,hypertension,andahistoryofpulmonary

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Figure 6. Electrogram (A) and catheter position (B) for Case 2. Before ablation, the lowest point for detection of His potential (in-dicated by arrows) was identified using the ablation catheter (d). (C) Electrogram and (D) catheter position at the time of ablation. Ablation was actually carried out at a lower point than that depicted in (B). His potential was not seen on the electrogram from the ablation catheter.a, duodecapolar catheter for right atrium and His; b, quadripolar catheter for His; c, quadripolar catheter for right ventricle

A

C

B

D

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tuberculosis.ATTEshowedpreservedleftven-

tricularejectionfraction(55%)andnostructural

abnormality.Chestradiographyandchestcom-

puted tomography showed a severely distorted

lung(Figure5),andcounter-clockwiserotation

oftheheart.InRAangiography,theRAexhibited

erectmorphology.AnEPinvestigationwassub-

sequentlyperformedusinga2-mmanda4-mm

quadripolarcatheter torecordHisandRVac-

tivity,respectively.Aduodecapolarcatheterwas

positionedattheCSandtheRA.Clinicaltachy-

cardiawasattributedtoslow-fastAVNRTonthe

basisofEPinvestigation.Duetothehighriskof

atrioventricular(AV)block,owingtothepatient’s

advancedageanddistortedheartstructure,the

ablation focus was carefully considered. First,

thelowestlevelfordetectionofHispotentialwas

identified(Figure6A,B).Next,aposteriorap-

proachwas taken, via themiddle or posterior

septalregionneartheCSostium(Figure6D).His

potentialwasnotobservedontheelectrogramof

theablationcatheter(Figure6C).Energydeliv-

eryresultedinsuccessfulinductionofjunctional

rhythm,thoughablationwasimmediatelyabort-

edonobservingventriculoatrial(VA)conduction

blocksomesecondslater.AhighdegreeofAV

blockwithconcurrenthypotensionoccurred.The

AVblockwas initially sustainedbuteventually

recoveredaftereighthours;thePRintervalnor-

malizedaftertwoweeks.

Discussion

AVNRTisoneofthemostcommontachyar-

rhythmias,andcanbetreatedbycatheterabla-

tion.Thiscanbehazardouswhentheslowpath-

wayisincloseproximitytothenormalconduction

system.Thus,aclearunderstandingofcardiac

anatomyisessentialbeforeAVNRTablation.

We have reported two complicated AVNRT

casesrelatedtorightheartanatomicabnormali-

ties.Inthefirstcase,anRAseptaldiverticulum

compromisedthepositioningandstabilityofthe

catheter.Binderetal.analyzed103casesofcon-

genitalmalformationsoftheRAandtheCS.2Of

the103casesstudied,13wereassociatedwithan

RAsinglediverticulumandthesewerepredomi-

nantlyasymptomatic.Thepresentationofsymp-

toms suchas supraventricular tachycardiawas

frequentlyinducedbyarrhythmia.

Wepresentthefirstreportedcaseofasingle

diverticulumintheRAseptum.Previousstudies

havereportedcasesofRAdiverticulapredomi-

nantlylocalizedtotheRAfreewallortheCS.2-7

TheRAseptaldiverticulumdescribedinthiscase

wasseparatedfromtheCS,asdemonstratedby

theangiogram.Becausethediverticulumexhib-

ited contractility consistentwith theheartbeat,

weruledoutthealternativediagnosisofseptal

aneurysm, in which contractility would not be

observed.8

Acquiredanatomicdistortionscanalsointer-

ferewithRFCAforAVNRT.Inthesecondcase,

safetywasensuredbyusingnumerousmethods:

(1)RAangiogram,(2)confirmationofthelowest

pointfordetectionofHispotential,(3)aposte-

riorapproachneartheCSostium,and(4)vigilant

observation ofVA conduction.A contemporary

transienthighdegreeAVblockwasnevertheless

seentooccur.

Foreffectiveandsafecatheterablationinpa-

tientswith anatomic obstacles, an overview of

thepreciseanatomyiscritical.Angiogramsand

carefulmappingcanfacilitatetheidentificationof

anatomicvariants,andcanconfirmprecisecath-

eterpositioning.

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Conclusion

WehavereportedtwodifficultAVNRTcasesre-

latedtorightheartanatomicvariation:thefirst,

anRAseptalaneurysm,andthesecond,heart

distortion due to tuberculosis-destroyed lung.

Anatomic obstacles can compromise successful

catheterablationforAVNRT.

Reference

1. Katritsis DG, Camm AJ. Atrioventricular nodal reentrant tachycardia. Circulation. 2010;122:831-840.

2. Binder TM, Rosenhek R, Frank H, Gwechenberger M, Maurer G, Baum-gartner H. Congenital malformations of the right atrium and the coro-nary sinus: an analysis based on 103 cases reported in the literature and two additional cases. Chest. 2000;117:1740-1748.

3. Morrow AG, Behrendt DM. Congenital aneurysm (diverticulum) of the right atrium. Clinical manifestations and results of operative treatment. Circulation. 1968;38:124-128.

4. Di Segni E, Siegal A, Katzenstein M. Congenital diverticulum of the heart arising from the coronary sinus. Br Heart J. 1986;56:380-384.

5. Pastor BH, Forte AL. Idiopathic enlargement of the right atrium. Am J Cardiol. 1961;8:513-518.

6. Morishita Y, Kawashima S, Shimokawa S, Taira A, Kawagoe H, Na-kamura K. Multiple diverticula of the right atrium. Am Heart J. 1990;120:1225-1227.

7. Sheldon WC, Johnson CD, Favaloro RG. Idiopathic enlargement of the right atrium. Report of four cases. Am J Cardiol. 1969;23:278-284.

8. Mugge A, Daniel WG, Angermann C, Spes C, Khandheria BK, Kronzon I, Freedberg RS, Keren A, Denning K, Engberding R, Sutherland GR, Vered Z, Erbel R, Visser CA, Lindert O, Hausmann D, Wenzlaff P. Atrial septal aneurysm in adult patients. A multicenter study using transthoracic and transesophageal echocardiography. Circulation. 1995;91:2785-2792.

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S Anatomical Obstacles to Catheter Ablation for