SIGNAL-AVERAGED ELECTROCARDIOGRAPHY AND VENTRICULAR-TACHYCARDIA AS PREDICTORS OF MORTALITY AFTER ACUTE MYOCARDIAL-INFARCTION IN ELDERLY PATIENTS

Signal-averaged electrocardiography and 24-hour ambulatory electrocard iographic monitoring were performed in 121 elderly patients >6 months after acute myocardial infarction. All patients had asymptomatic compl ex ventricular arrhythmias and a left. ventricular ejection fraction g reater than or equal to 40%. Rates of sudden, cardiac, and total death were compared between groups with and without nonsustained ventricula r tachycardia and between normal and abnormal signal-averaged electroc ardiographic studies. The prevalence of an abnormal signal-averaged el ectrocardiographic study was 36%. Thirty-seven percent of the patients had nonsustained ventricular tachycardia, and the remaining patients had complex ventricular arrhythmias other than ventricular tachycardia . There were 27 sudden and 48 total cardiac deaths, and 66 deaths from all causes during a mean follow-vp period of 30 months. Kaplan-Meier survival analysis showed a lower rate of sudden and cardiac death in t he group without nonsustained ventricular tachycardia. Although there was a trend toward a lower rate of sudden death in patients with a nor mal signal-averaged electrocardiogram, there was no statistical differ ence in the rates of sudden, total cardiac, or total death between pat ients with normal or abnormal studies. The negative predictive value o f having neither an abnormal signal-averaged electrocardiogram nor non sustained ventricular tachycardia was 94% for sudden death. In elderly patients with complex ventricular arrhythmias and election fraction g reater than or equal to 40% at least 6 months after an acute myocardia l infarction, presence of nonsustained ventricular tachycardia predict ed a higher rate of sudden and cardiac death. Signal-averaged electroc ardiography alone was not predictive.