Signal-Averaged ECG
Signal-averaged ECG is a non-invasive test done to detect evidence of ventricular electrical conduction delay. It has utility in select groups of patients. Specifically it has been found to be useful in identifying an increased risk of sudden death in patients with ischemic heart disease. It is useful also in establishing the diagnosis of arrhythmogenic right ventricular dysplasia. A signal-averaged ECG is performed by placing six electrodes on the chest and back and one on the abdomen. Similar to the stress test, the skin at each electrode site is gently abraded to insure high-quality, noise-free recording. The electrodes are attached to a small computer that, over a 20-minute period, records multiple ECGs and averages them to produce a high fidelity, low-noise ECG. The test requires patients to lie very still but is brief (approximately 20 minutes), non-invasive, and painless.
