[Prognostic significance of programmed ventricular stimulation in the noninvasive registration of ventricular late potentials in the postinfarct period].

The prognostic significance of programmed ventricular stimulation for assessing ventricular vulnerability and of signal averaging for detection of ventricular late potentials was assessed prospectively in 132 survivors of acute myocardial infarction. The median day of these studies was the 22nd. Programmed ventricular stimulation (PVS) included single and double premature stimuli during sinus rhythm and paced ventricular rhythms at rates of 120, 140, 160 and 180 bpm. The endpoint for stimulation was the induction of 4 or more consecutive echo beats. 59 of 132 patients (45%) had late potentials in their body surface signal-averaged ECG. The prevalence was 35% in those with anterior wall infarction and 54% in those with inferior wall infarction (chi 2 = 3.9; p less than 0.05). In 61 patients (46%), 4 or more consecutive echo beats were induced. In 28 of these patients, sustained ventricular tachycardia or fibrillation were initiated. During follow-up (15 +/- 11 months; mean +/- S.D.), there were 4 sudden deaths. Neither PVS nor signal averaging were able to predict these events. Spontaneous symptomatic sustained ventricular tachycardia occurred in a total of 9 patients, all of whom had an abnormal PVS result (sensitivity 100%); 7 of these patients also had late potentials (sensitivity 78%). Stepwise analysis revealed that the combination of late potentials (duration greater than or equal to 40 ms), and of induction of sustained ventricular tachycardia at rates less than 270 bpm had the highest predictive value (50%). In contrast, the prevalence of sustained ventricular tachycardia was as low as 3% in those without late potentials.(ABSTRACT TRUNCATED AT 250 WORDS)