Prognostic features of 115 patients with ventricular tachycardia complicating acute myocardial infarction were analyzed. Age, sex, infarct location and peak CPK levels were not significantly different when comparing survivors (S) and non-survivors (NS). Highly significant clinical characteristics of NS compared to S were: heart rate, presence of cardiogenic shock and a poor response to lidocaine therapy (P less than 0.0001, 0.0003 and 0.001 respectively). Electrocardiographic features distinguishing S and NS were: coupling intervals (S = 522.9, NS = 389.9, P less than 0.004), prematurity index (S = 1.36, NS = 1.04, P less than 0.001), ventricular tachycardia rate (S = 132, NS = 174, P less than 0.0013) and number of episodes of ventricular tachycardia (S = 4.04, NS = 6.75, P less than 0.0058). These findings have importance for the evaluation of newer active and prophylactic therapies.