SIGNAL-AVERAGED ELECTROCARDIOGRAPHY IN PATIENTS WITH ACUTE MYOCARDITIS

This report describes the late potentials obtained by signal averaged electrocardiography (EGG) in 19 patients (13 male, 6 female, mean age 31 +/- 17 years) with acute myocarditis and their evolution. Five pati ents (26%) had positive signal averaged ECG in time domain analysis an d two had technically inadequate signal averaged EGG. All five patient s with positive signal averaged EGG, and 6 of the 12 patients with neg ative, developed heart failure (100%). One patient died. Signal averag ed ECG was repeated at 3 months in all 18 surviving patients. Two pati ents had a good clinical evolution, normalized left ventricular functi on, and changed from positive to negative signal averaged EGG. All pat ients with heart failure on admission with negative signal averaged EC G had clinical improvement. Late potentials in patients with acute myo carditis are associated with a worse prognosis and greater extent of m yocardial damage.