[Correlations between the different criteria of late potentials and results of programmed ventricular stimulation after myocardial infarction]

Abstract

Five to ten per cent of survivors of acute myocardial infarction die within two years. The majority of these deaths are sudden and are attributed to a lethal ventricular arrhythmia. This is usually ventricular tachycardia degenerating to ventricular fibrillation. These post-infarction tachycardias are generally due to reentry. They require an anatomic arrhythmogenic substrate, a zone of delayed conduction. This can be detected as late potentials on signal averaged ECG. The triggering of a significant ventricular arrhythmia by ventricular stimulation is closely correlated to the occurrence of a severe ventricular arrhythmia in the months following infarction. Programmed ventricular stimulation could, therefore, help to identify patients requiring close follow-up and/or preventive antiarrhythmic therapy, but cannot be offered to all patients because of its invasive nature. Seventy nine post-infarction patients were studied prospectively. All underwent coronary angiography, signal averaging electrocardiography, and programmed ventricular stimulation at least 15 days after infarction. Fifty five patients had at least one criterion of late potentials (QRS duration > or = 110 ms and/or amplitude of the last 40 ms < 27 microV and/or duration of potentials of under 40 microV > 37 ms). Twenty four patients had no late potentials. The results of programmed stimulation were estimated to be positive when sustained or unsustained monomorphic ventricular tachycardia was triggered, and negative when ventricular fibrillation, ventricular flutter unsustained polymorphic ventricular tachycardia or no arrhythmia could be induced. Programmed ventricular pacing triggered 15 significant events, 17 unsustained polymorphic ventricular tachycardias, 13 ventricular flutters and 11 ventricular fibrillations. The exploration was negative in 23 patients.(ABSTRACT TRUNCATED AT 250 WORDS)