[Evaluation of the arrhythmogenic potential 3 months after myocardial infarction]

Abstract

An evaluation of the ventricular arrhythmia potential was conducted 3 months after a myocardial infarction (anterior n = 32, inferior n = 58) in 90 patients with a group mean age of 58 +/- 9.3 years, using 24-hour ambulatory ECG monitoring, an exercise test, recording of late ventricular potentials and programmed right ventricular stimulation. Eighteen patients (20%) had a ventricular extrasystole > or = Lown grade III on the Holter, which was more frequent in patients with ventricular dyskinesia (41% vs 15%; p < 0.05); 10 patients (11.1%) had ventricular extrasystoles > or = Lown grade III during the exercise test; 19 patients had late ventricular potentials. Programmed ventricular stimulation induced monomorphic ventricular tachycardia in 10 patients (11.1%) (sustained, n = 5, unsustained n = 5) and the prevalence of late ventricular potentials was higher in this group (60% vs 16.2%; p < 0.01). In the medium term (32 months), 2 patients had died: one suddenly and the other of a recurrence of myocardial infarction. Five patients had an episode of spontaneous ventricular tachycardia. The risk of sudden death or ventricular tachycardia was higher in patients with late ventricular potentials (positive predictive value = 21%) and in patients with electro-induced ventricular tachycardia (positive predictive value = 66%). In the absence of late ventricular potentials, the risk of a serious arrhythmic event is slight (2.8%). After myocardial infarction, the presence of late ventricular potentials can be used to isolate a group of patients with a high risk of serious ventricular arrhythmia; this risk is higher if programmed ventricular stimulation triggers monomorphic ventricular tachycardia.