Suppression of Incessant Ventricular Tachycardia in Hypertrophic Cardiomyopathy Associated with Improvement of Severe Left Ventricular Dysfunction DOROTHEA McAREAVEY and LAMEH EANANAPAZIR From the Cardiology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland

McAREAVEY, D., ET AL.: Suppression of Incessant Ventricular Tachycardia in Hypertrophic Cardiomyopathy Associated with Improvement of Severe Lefl Ventricular Dysfunction. A 32-yeaT-old black man presented with a history of paipitations since childhood and two syncopal episodes. He was found to have incessant ventricular tachycardia, impaired left ventricuiar contraction (ejection fraction 9%), and nonobstructive hypertrophic cardiomyopathy. Procainamide aboJished the arrhythmia and the ejection fraction rose to 22% in sinus rhythm. Later treatment was switched to amiodarone, which suppressed the ventricular tachycardia but necessitated pacemaker impJantation. He has remained well during the subsequent 2 years. Left ventricular ejection fraction has increased to 47% measured in paced rhythm. The improvement in left ventricular function has been attributed to suppression of the incessant ventricuiar tachycardia. (PACE, Vol. 15, November, Part / 1992} incessant ventricuiar tachycardia, hypertrophic cardiomyopathy, left ventricular dysfunction Introduction Dilated cardiomyopathy due to incessant atrial tachycardia is uncommon but well recognized.^'^ Tbe diagnosis is made when treatment of the arrhythmia results in improvement of the left ventricular function.^ Nonischemic incessant ventricular tachycardia associated with left ventricular dysfunction is rare.' We report treatment of a longstanding incessant ventricular tachycardia in hypertrophic cardiomyopathy associated with marked improvement of coexistent severe left ventricular dysfunction. Case Report The patient is a 32-year-old black male who was referred to tbe National Institutes of Health in

Address for reprints: Lameh Fananapazir, M.D., Director, Clinical Electrophysiology Laboratory, Room 7B-14, Building 10, National Institutes of Health, 9000 Rockville Pike, Bethesda. MD 20892. Fax: (301) 402-0888. Received Fehruary 10, 1992; revision May 14. 1992; revision July 6, 1992; accepted July 14, 1992.

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October 1989 because of a history of palpitations and two episodes of syncope. At the age of 10 years, the diagnosis of incessant ventricular tachycardia had been made from the 12-lead ECG and Holter recordings. The arrhythmia, however, had not been investigated further, and had not been suppressed by propranolol or digoxin therapy. Physical examination revealed an irregular pulse, normal blood pressure, and an enlarged heart. There was no evidence of overt cardiac failure. The ECG showed bursts of a wide complex tachycardia [rate 142 beats/min; QRS width 140 msec; right bundle branch with left axis configuration), terminating in single sinus beats (Fig. 1). Echocardiographic findings were: left ventricular diastolic dimension 61 mm; left ventricular systolic dimension 45 mm; apical left ventricular hypertrophy with distal interventricular septal thickness of 20 mm and left ventricular posterior wall thickness of 12 mm; and left atrial dimension of 51 mm. There was no evidence of valvular disease, ethanol use, or other cause for the left ventricular hypertrophy or dilatation. It was therefore determined that the patient had nonobstructive hypertrophic car-

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Figure 1. Twelve-lead ECG prior to procainamide infusion showing burst of wide complex tachycardia (rate 142 beats/min; QRS widlh 140 msec; right bundle branch with Je/f axis con/igurationj inlerrupted by single sinus beats (arroivsj.

diomyopathy, which had entered a dilated phase. The diagnosis of familial hypertrophic cardiomyopathy was established by the finding of nonobstructive hypertrophic cardiomyopathy in a brother, and a history that the patient's father had died suddenly and prematurely. Radionuclide angiography revealed a resting left ventricular ejection fraction of 9% measured during ventricular tachycardia. The findings at cardiac catheterization were: mean right atrial pressure 6 mmHg; right ventricular pressure 22/7 mmHg; pulmonary arterial pressure 20/8 mmHg; mean pulmonary arterial capillary wedge pressure 12 mmHg; left ventricular pressure 80/12 mmHg; aortic pressure 80/60 mmHg; and cardiac index 1.8 L/min/m^. At electrophysiological stndy, the diagnosis of ventricular tachycardia [mean cycle length 440 msec) was established by the presence of atrioventricular (AV) dissociation. Following infusion of procainamide (10 mg/kg), the spontaneous arrhythmia was eliminated and a 12-lead ECG showed sinus rhythm with premature atrial complexes (Fig. 2) and features of left ventricular hypertrophy. The

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A-H and H-V intervals were 70 msec and 60 msec, respectively. No attempt was made to induce the ventricular tachycardia. On oral procainamide [4 g/day), the radionuclide resting left ventricular ejection fraction in sinus rhythm was only 22%. The patient, however, was unable to tolerate procainamide and therapy was switched to amiodarone. After a loading dose of 800 mg/day for 2 weeks, and on a maintenance dose of 400 mg/day, amiodarone completely suppressed the ventricular arrhythmia. The patient developed sinus bradycardia and junctional escape rhythms, necessitating implantation of a dual chamber permanent pacing device. At 2-year follow-up, he was asymptomatic and was able to perform 9.75 minutes of treadmill exercise (Bruce protocol), limited only by leg fatigue. The radionuclide left ventricular ejection fraction had increased to 47% and echocardiographic evaluation showed marked reduction of the left ventricular dimensions: 48 mm in diastole and 31 mm in systole. The maximum left ventricular wall thickness (interventricular septum) was unchanged, measuring 20 mm.

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McAREAVEY. ET AL.

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Figure 2. Twelve-lead ECG following suppression of the ventricular tachycardia with procainamide showing features consistent with left venfricuiar hypertrophy.

Discussion One or more episodes of ventricular tachycardia may he recorded in 25% of hypertrophic cardiomyopathy patients during 24-48 hours of Holter monitoring.** These are, however, usually hrief and not associated with significant symptoms. In contrast, ventricular arrhythmias that cause sudden death or are induced at electrophysiological study are usually rapid polymorphic or monomorphic ventricular tachycardia.'* This to our knowledge is the first report of an incessant ventricular tachycardia in hypertrophic cardiomyopathy. Although it caused palpitations and was most probably implicated in the onset of syncope, the ventricular tachycardia was otherwise surprisingly well tolerated. It was, however, associated with left ventricular dilatation and severe dysfunction. Effective treatment of the ventricular tachycardia resulted in dramatic reduction in left ventricular dimensions and improvement of left ventricular function. About 5% of patients with hypertrophic cardiomyopathy develop left ventricular dilatation and dysfunction. These patients are prone to arrhyth-

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mias and sudden death, but treatment of associated cardiac failure and arrhythmias does not result in marked reversal of the left ventricular enlargement and dysfunction. These patients are, therefore, often candidates for cardiac transplantation. We therefore believe that in the absence of any other identifiable cause, the left ventricular dysfunction in our patient was due to the incessant ventricular tachycardia. The mechanism by which an incessant tachyarrhythmia induces left ventricular dysfunction is not clearly understood.^ However, the dilated cardiomyopathy may be related to chronic depletion of adenosine triphosphate necessary for contraction.^ The cardiac state of our patient prior to the onset of the arrhythmia is unknown. It is possible that the tachycardia was responsible for the left ventricular hypertrophy. However, the persistence of left ventricular hypertrophy following treatment of the tachycardia and a family history of hypertrophic cardiomyopathy strongly suggest the diagnosis of ventricular tachycardia secondary to hypertrophic cardiomyopathy in this patient. Sinus node disease and His-Purkinje conduction abnormalities are common in hypertrophic cardio-

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m y o p a t h y and may be aggravated by amiodarone.'^ In this patient, these factors resulted in the need for p e r m a n e n t dual chamber pacing. Despite the resulting a s y n c h r o n o u s ventricular contraction, the left v e n t r i c u l a r ejection fraction improved

from 22% (in sinus rhythm) to 47% at 2 years of follow-up. If the improvement in symptoms and left ventricular function is maintained, it would be unnecessary to consider cardiac transplantation.

References 1.

2.

3.

SwerdlowCD. Liem LB. Atrial and junctional tachycardias: Clinical presentation, course and therapy. In DP Zipes, J Jalife (eds,): Cardiac Electrophysiology. From Cell to Bedside. Philadelphia, PA, WB Saunders Co., 1990, pp. 742-755. Ziegler VL, Gillette PC, Crawford FA, et al. New approaches to treatment of incessant ventricular tachycardia in the very young. J Am Coll Cardiol 1990; 16:681-685. Gallagher JJ. Tachycardia and cardiomyopathy: The chicken-egg dilemma revisited. J Am Coll Cardiol 1985; 6:1172-1173.

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Fananapazir L, Epstein SE. Hemodynamic and electrophysiologic evaluation of patients with hypertrophic cardiomyopathy surviving cardiac arrest. Am j Cardiol 1991; 67:280-287. Coleman HN, Taylor RR, Pool PE, et al. Congestive heart failure following chronic tachycardia. Am Heart J 1971; 81;790-798. Fananapazir L, Epstein SE. Value of electrophysiologic studies in hypertrophic cardiomyopathy treated with amiodarone. Am J Cardiol 1991; 67: 175-182,

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Suppression of incessant ventricular tachycardia in hypertrophic cardiomyopathy associated with improvement of severe left ventricular dysfunction.

A 32-year-old black man presented with a history of palpitations since childhood and two syncopal episodes. He was found to have incessant ventricular...
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