PROGNOSTIC VALUE OF THROMBOLYSIS, CORONARY-ARTERY POTENCY, SIGNAL-AVERAGED ELECTROCARDIOGRAPHY, LEFT-VENTRICULAR EJECTION FRACTION, AND HOLTER ELECTROCARDIOGRAPHIC MONITORING FOR LIFE-THREATENING VENTRICULAR ARRHYTHMIAS AFTER A FIRST ACUTE MYOCARDIAL-INFARCTION

Prognostic studies after acute myocardial infarction (AMI) have mainly been performed in the prethrombolytic era. Despite the fact that mode rn management of AMI has reduced mortality rates, the occurrence of ma lignant ventricular arrhythmias in the late phase of AMI remains an im portant issue. We prospectively studied 244 consecutive patients (97 t reated with thrombolytics) who survived a first AMI. All patients unde rwent time domain signal-averaged electrocardiography (vector magnitud e: measurements of total QRS duration, terminal low [<40 mu V] amplitu de signal duration, and root-mean-square voltage of the last 40 ms of the QRS complex), Holter electrocardiographic monitoring, and cardiac catheterization. late life-threatening ventricular arrhythmias were re corded. Eighteen arrhythmic events occurred during a mean follow-up pe riod of 57 +/- 18 months. Three independent factors were associated wi th a higher risk of arrhythmic events: (1) left ventricular ejection f raction (odds ratio 1.9/0.10 decrease), (2) terminal low-amplitude sig nal duration (odds ratio 1.5/5 ms increase), and (3) absence of thromb olytic therapy (odds ratio 3.9). Low-amplitude signal duration sensiti vity for sudden cardiac death was low (30%). Left ventricular ejection fraction had the highest positive predictive value for sudden cardiac death (10%). Thus, thrombolysis decreases both the incidence of ventr icular tachycardia and sudden cardiac death with a higher reopening ra te of the infarct-related vessel. Signal averaging predicts the occurr ence of ventricular tachycardia and an impaired left ventricular eject ion fraction predicts the occurrence of sudden cardiac death. (C) 1997 by Excerpta Medica, Inc.