Noninvasive identification of patients at risk for ventricular tachycardia with the signal-averaged electrocardiogram.

The signal-averaged electrocardiogram (SAE) is a noninvasive means of detecting cardiac late potentials. Late potentials in patients with coronary artery disease indicate a high risk for the development of ventricular tachycardia. Although the usefulness of the SAE for directing therapy has not yet been clearly established, the test appears to be useful in the stratification of arrhythmia risk in select groups of high-risk patients. As critical care nurses frequently care for these patients, they need to be familiar with tools such as the SAE that may be used in high-risk patient assessment. This article describes the physiologic basis underlying the use of the SAE, the SAE technique, implications for nursing practice, and clinical applications of the SAE.