Arrhythmia recurrence in patients with a healed myocardial infarction who received an implantable defibrillator: Analysis according to the clinical presentation

OBJECTIVES The purpose of this study was to analyze the type of arrhythmia recurrence, based on stored electrograms, in patients with a healed myocard ial infarction (MI) who received an implantable defibrillator. BACKGROUND Previous studies suggest that patients presenting with cardiac a rrest (CA) tend to recur as ventricular fibrillation (VF), whereas those su ffering sustained monomorphic ventricular tachycardia (SMVT) tend to recur as SMVT. However, these data have not been confirmed in a homogeneous popul ation of patients with MI. METHODS A total of 88 patients was divided into three groups according to t heir clinical presentation: SMVT (n = 57), CA (n = 16) or syncope (n = 15). RESULTS There were no significant dfferences in clinical characteristics am ong groups. In the electrophysiologic study SMVT was induced in 93%, 94% an d 80% of patients, respectively (p = NS). During the follow-up period, 52% of patients presented a total of 671 episodes of ventricular arrhythmia tre ated by the defibrillator. All recurrences were as SMVT except for one VF. There were 610 episodes of SMVT treated with antitachycardia pacing, with a n effectiveness of 96%. A total of 61 episodes was treated initially with c ardioversion. No differences in the probability of recurrence were observed among groups, although the statistical power was low (50%). CONCLUSIONS In patients with an old infarction and malignant ventricular ar rhythmias, the majority of recurrences are due to SMVT independently of the clinical presentation (SMVT, CA or syncope) or the induced arrhythmia at t he electrophysiologic study. The programming of an antitachycardia zone see ms to be appropriate also for patients who present with CA or syncope. (C) 1999 by the American College of Cardiology.