Noninvasive identification of patients at high risk for sudden cardiac death. Signal-averaged electrocardiography.

Signal-averaged electrocardiography allows the detection of late potentials, which have been associated with delayed and disorganized ventricular activation. This article reviews the technique, describes the findings recorded from patients with ventricular tachyarrhythmias, and assesses the prognostic value of late potentials for ventricular tachyarrhythmias and sudden cardiac death in patients after an acute myocardial infarction. The role of signal-averaged electrocardiography in the evaluation of patients with syncope and cardiomyopathies is also briefly discussed.