Coronary artery revascularization in patients with sustained ventricular arrhythmias in the chronic phase of a myocardial infarction: effects on the electrophysiologic substrate and outcome

OBJECTIVES The objective of this study was to analyze the influence of coronary artery revascularization in patients with ventricular arrhythmias. BACKGROUND Coronary artery revascularization is an effective treatment for myocardial ischemia; however, its effect on ventricular arrhythmias not related to an acute ischemic event has not been carefully studied. METHODS Sixty-four patients (58 men, mean age 65 ± 8 years old) with prior myocardial infarction, spontaneous ventricular arrhythmias not related to an acute ischemic event (55 ventricular tachycardia, 9 ventricular fibrillation) and coronary lesions requiring revascularization were studied prospectively. Electrophysiological study was performed before and after revascularization, and events during follow-up were analyzed. RESULTS At initial study 61 patients were inducible into sustained ventricular arrhythmias. After revascularization, in 62 survivors, 52 out of 59 patients previously inducible were still inducible (group A), and 10 patients were noninducible (group B). No differences were found in clinical, hemodynamic, therapeutic and electrophysiological characteristics between both groups. During 32 ± 26 months follow-up, 28/52 patients in group A (54%) and 4/10 patients in group B (40%) had arrhythmic events (p = 0.46). An ejection fraction <30% predicted recurrent arrhythmic events (p = 0.02), but not the presence of demonstrable ischemia before revascularization (p = 0.42), amiodarone (p = 0.69) or beta-adrenergic blocking agent therapy (p = 0.53). Total mortality was 10% in both groups. CONCLUSIONS In patients with ventricular arrhythmias in the chronic phase of myocardial infarction, probability of recurrence is high despite coronary artery revascularization, but mortality is low if combined with appropriate antiarrhythmic therapy. Recurrences are related to the presence of a low ejection fraction but not to demonstrable ischemia before revascularization, amiodarone or beta-blocker therapy nor are they the results of electrophysiological testing after revascularization.