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Repeated Radiofrequency Ablation of Atrial Tachycardia inRestrictive Cardiomyopathy Secondary to Myofibrillar

MyopathyCLAUDIA STOLLBERGER, M.D.,∗ EDMUND GATTERER, M.D.,∗ JOSEF FINSTERER, M.D.,

Ph.D.,∗ KARL-HEINZ KUCK, M.D.,† and ROLAND RICHARD TILZ, M.D.†From the ∗Krankenanstalt Rudolfstiftung, Wien, Austria; and †Asklepios-Klinik St. Georg, Department of Cardiology, Hamburg,

Germany

Radiofrequency Ablation in Restrictive Cardiomyopathy. Myofibrillar myopathy is character-ized by nonhyaline and hyaline lesions due to mutations in nuclear genes encoding for extra-myofibrillaror myofibrillar proteins. Cardiac involvement in myofibrillar myopathy may be phenotypically expressedas dilated, hypertrophic, or restrictive cardiomyopathy. Radiofrequency ablation of atrial fibrillation andflutter has so far not been reported in myofibrillar myopathy. We report the case of a young female with my-ofibrillar myopathy and deteriorating heart failure due to restrictive cardiomyopathy and recurrent atrialfibrillation and atrial tachycardias intolerant to pharmacotherapy. Cardiac arrhythmias were successfullytreated with repeat radiofrequency ablations and resulted in regression of heart failure, thus postponingthe necessity for cardiac transplantation. (J Cardiovasc Electrophysiol, Vol. 25, pp. 905-907, August 2014)

atrial fibrillation, atrial tachycardia, heart failure, myopathy, radiofrequency ablation, restrictive cardiomyopathy

Introduction

Myofibrillar myopathies (MFMPs) are rare myopathiesdue to mutations in nuclear genes encoding for extra-myofibrillar or myofibrillar proteins.1 Cardiac involvementin MFMPs has been reported as dilated, hypertrophic, orrestrictive cardiomyopathy (RCMP) associated with heartfailure and arrhythmias.2-4 Radiofrequency ablation of atrialfibrillation (AF) and atrial tachycardia (AT) has so far notbeen reported in MFMP. We report the course of a patientwith previously described MFMP and RCMP, whose symp-tomatic atrial flutter and AF were treated by radiofrequencyablation.5

Case Report

In a 23-year-old Caucasian female with a history of tip-toewalking since early childhood, contractures of the elbow andknee joints, exertional dyspnea, and scoliosis since the age of10 years, RCMP was first diagnosed at age 12 years. Cardiaccatherization at age 14 years revealed normal coronary ar-teries and left ventricular systolic function. Endomyocardialbiopsy showed hypertrophic cardiomyocytes, enlarged nu-clei, vacuolated cytoplasm, an increase in interstitial fibroustissue, perivascular infiltrates of histiocytes, and edema.

R.R. Tilz reports participation on research grants supported by St. JudeMedical and Hansen Medical; he received compensation for participationon a speaker’s bureau from Biosense Webster. K.H. Kuck reports travelgrants and spesker’s honoraria from Biosense Webster, St. Jude Medical,Abbott Vascular, and Medtronic. Other authors: No disclosures.

Address for correspondence: Claudia Stollberger, M.D., KrankenanstaltRudolfstiftung, Steingasse 31/18, A-1030 Wien, Osterreich, Austria. Fax:43-171-165-2209; E-mail: claudia.stoellberger@chello.at

Manuscript received 19 February 2014; Revised manuscript received 12April 2014; Accepted for publication 17 April 2014.

doi: 10.1111/jce.12436

At age 19 in 2009, exercise intolerance and exertionaldyspnea increased. ECG showed first degree atrioventricularblock, biphasic P waves, right axis deviation, and repolar-ization abnormalities. Twenty-four-hour electrocardiogram(ECG) revealed 5 episodes of AT lasting up to 15 seconds and1 episode of sinus tachycardia. Bisoprolol was not toleratedbecause of hypotension and bradycardia. Two months later,she developed peripheral edema treated with spironolactoneand furosemide. ECG showed atrial flutter with a ventric-ular rate of 50–70/min and oral anticoagulation with phen-procoumon was started. Electrical cardioversion in February2010 restored sinus rhythm, associated with clinical improve-ment. Muscle biopsy from the right lateral vastus musclewas indicative of MFMP, most likely a desmin myopathy.Sequencing of the desmin gene, however, did not identify acausative mutation.

In November 2010 and June 2011, 2 further electrical car-dioversions for AT were required to restore sinus rhythm. Dueto recurrent episodes of AT and AF causing heart failure andrequiring repeated electrical cardioversion, and β-blockerswere not tolerated, the patient was referred for electrophysi-ological (EP) study and catheter ablation in November 2011.At the initial EP study, the patient was in AF. After doubletransseptal punctures, 3D-electroanatomic mapping using theCARTO

TMsystem (Biosense Webster Inc., Diamond Bar, CA,

USA) was performed and revealed large areas of low voltagedefined as <0.5 mV. Pulmonary vein isolation was performedas previously described.6 The patient converted into multipleleft and right ATs requiring right and left atrial isthmus abla-tion, as well as ablation of a left atrial anterior line resultingin accidental electrical isolation of the left atrial appendage.Sinus rhythm was obtained by electrical cardioversion ofperimitral flutter prior to left atrial isthmus ablation. Bidi-rectional block of all lines was achieved and isolation of thepulmonary veins was confirmed by assessment for entranceblock using a spiral catheter (Lasso, Biosense Webster Inc.)during sinus rhythm.

The patient remained in stable sinus rhythm until May2013, when AT recurred and she presented with NYHA IV

906 Journal of Cardiovascular Electrophysiology Vol. 25, No. 8, August 2014

Figure 1. Three-dimensional electroan-atomical reconstruction and voltage mapof the left and right atrium in posterioranterior projection at the second abla-tion procedure. Pink indicates a voltageof greater than 0.5 mV; all other colorsindicate low voltage defined as less than0.5 mV. Please note the large low voltagearea in both the left and the right atrium.White tags in the right atrium mark theostium of the superior vena cava. Whitetags in the left atrium mark the ostiumof the left pulmonary veins (PVs). Darkred tags mark ablation points. Please notethat ablation was solely performed ante-rior and posterior to the left PVs in orderto reisolate the PVs and to ablate ostialpotentials.

Figure 2. Three-dimensional electroanatomical reconstruction and voltage map of the left and right atrium in posterior anterior projection (A) and the leftatrium in anterior posterior projection (B) at the third ablation procedure. Cut-off values for voltage are as in Figure 1. White tags in the left atrium markthe pulmonary vein ostium. Red tags indicate ablation points. Blue and yellow tags indicate pacing sites. Please note the multiple ablation sites in the leftatrial posterior wall, left atrial isthmus, right atrial septum close to and within the coronary sinus, and the left atrial anterior wall.

decompensated cardiac failure. Again, β-blockers were nottolerated. Because of the hemodynamic deterioration, thepatient was listed for cardiac transplantation. Sinus rhythmwas achieved by electrical cardioversion; however, AT re-curred 2 weeks later. Thus, she underwent repeat ablationprocedures in July 2013. During EP study, 15 different leftand right ATs with cycle lengths ranging from 290 to 600milliseconds were induced. The earliest activation was pre-

dominantly in the right atrium. The tachycardias convertedspontaneously into other ATs or into sinus rhythm. The lateralpulmonary veins showed electrical reconduction and weresuccessfully reisolated by closing the conduction gap in theprevious ablation line with focal ablation (Fig. 1). In addi-tion, ostial potentials along the previous ablation line wereablated. The right pulmonary veins and left atrial appendagewere still isolated. In a further procedure (Fig. 2) 7 days later,

Stollberger et al. Radiofrequency Ablation in Restrictive Cardiomyopathy 907

multiple left and right ATs were treated by focal ablation inthe left atrial posterior wall and the coronary sinus, and bylinear ablation of a low anterior line in the left atrium aswell as by infra-hisian right atrial ablation. At the end ofthe procedure, solely a nonsustained right AT was inducible.Mapping of this AT was performed in the left atrium, rightatrium, and aorta. The earliest local electrogram was iden-tified in the right atrium at the His region and preceded theP wave by 50 milliseconds. Because of the risk of total AVblock, no ablation was performed.

Following these procedures the arrhythmia burden de-creased, and heart failure regressed. Twenty-four-hour Holtermonitoring in September 2013 showed only short episodesof AT with the longest duration lasting 18 seconds at a rate of110/min. The postinterventional course was complicated byan arteriovenous fistula in the right groin requiring surgicalcorrection and a seroma requiring mechanical compressionand lymphatic drainage. In April 2014, the patient suffersonly from short episodes of AT and is in the NYHA stage Iof heart failure.

Discussion

Therapeutic options in RCMP include lowering of theheart rate to improve left ventricular filling, diuretics totreat edema, pacemaker implantation in case of brady-cardia, oral anticoagulation in atrial flutter or fibrillationto prevent thromboembolism, or heart transplantation.2,3,7,8

In our case, few options were available, as any therapyused for AT control led to hypotension and bradycardiawhen the patient was in sinus rhythm. Apart from di-uretic agents to relieve congestion, no other therapy wasfeasible.

AF or flutter is a frequent finding in patients withRCMP. These arrhythmias are exacerbated by the enlarge-ment of both atria as a consequence of the disturbed com-pliance of the ventricular myocardium. Most likely, car-diac involvement in MFMP may additionally contribute tothe arrhythmogenic potential within the atria. Myocardio-cytes in MFMP causing RCMP show cytoplasmic granulo-filamentous inclusions that continue with the Z-lines and areimmunoreactive for desmin filaments.2,4,9 These findings arederived from endomyocardial biopsies and pathoanatomicinvestigations of the ventricles. To our knowledge, noprevious investigations have explicitly assessed the atrialcardiomyocytes in MFMP patients. Furthermore, no patho-physiologic explanation for the electrical instability of theatria as a consequence of the contractile disturbance isavailable.1 It is speculated that mutant desmin interfereswith the normal assembly of intermediate filaments, resultingin fragility of the myofibrils and severe dysfunction of thecardiomyocytes.10

Achievement of rate control is important in RCMP caseswith tachycardia to improve ventricular filling and maintain

cardiac output. If rate control cannot be achieved, AV-nodeablation with pacemaker implantation has previously beenthe only option in these patients. This has been only reportedin a single patient with MFMP and RCMP.2 As demonstratedin our case, radiofrequency ablation in a highly experiencedcenter may be an additional option for these patients. Abla-tion does not cure this kind of cardiomyopathy. However, itmay successfully treat the cardiac arrhythmia and thereforecan lead to regression of heart failure, thus postponing thenecessity for cardiac transplantation.

Conclusion

This case demonstrates that in patients with RCMP due toMFMP and atrial arrhythmias, catheter ablation of multipleatrial arrhythmias can lead to regression of heart failure. Itillustrates the complexity of the ablation procedure due tothe underlying disease. Therefore, such procedure shouldonly be performed in a highly experienced center. In highlyexperienced hands, repeated radiofrequency ablation maydelay heart transplantation in patients with RCMP.

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