Familial cardiomyopathy underlies syndrome of right bundle branch block, ST segment elevation and sudden death

Abstract

Objectives: We sought to assess whether structural heart disease underlies the syndrome of right bundle branch block, persistent ST segment elevation and sudden death.

Background: Ventricular fibrillation and sudden death may occur in patients with a distinctive electrocardiographic (ECG) pattern of right bundle branch block and persistent ST segment elevation in the right precordial leads.

Methods: Sixteen members of a family affected by this syndrome underwent noninvasive cardiac evaluation, including electrocardiography, Holter ambulatory ECG monitoring, stress testing, echocardiography and signal-averaged electrocardiography; two patients had electrophysiologic and angiographic study. Endomyocardial biopsy was performed in one living patient, and postmortem examination, including study of the specialized conduction system, was performed in one victim of sudden death.

Results: Five years before a fatal cardiac arrest, the proband had been resuscitated from sudden cardiac arrest due to recorded ventricular fibrillation. Serial ECGs showed a prolonged PR interval, right bundle branch block, left-axis deviation and persistent ST segment elevation in the right precordial leads, in the absence of clinical heart disease. Postmortem investigation disclosed right ventricular dilation and myocardial atrophy with adipose replacement of the right ventricular free wall as well as sclerotic interruption of the right bundle branch. A variable degree of right bundle branch block and upsloping right precordial ST segment was observed in seven family members; four of the seven had structural right ventricular abnormalities on echocardiography and late potentials on signal-averaged electrocardiography. A sib of the proband also had a prolonged HV interval, inducible ventricular tachycardia and fibrofatty replacement on endomyocardial biopsy.

Conclusions: An autosomal dominant familial cardiomyopathy, mainly involving the right ventricle and the conduction system, accounted for the ECG changes and the electrical instability of the syndrome.