Ischemia, a common trigger for arrhythmias, is a well-documented cause of repolarization alternans. Human studies have shown that active ischemia can be associated with visible as well as microvolt-level T-wave alternans. While MTWA testing is traditionally used to evaluate arrhythmic risk, this known association with ischemia may allow MTWA testing to be used as a diagnostic tool to detect underlying CAD. The MTWA-CAD study will assess the feasibility of this concept by measuring MTWA during routine nuclear stress testing or stress echocardiography with treadmill exercise. This is a feasibility study designed to verify preliminary observations under controlled environments and to generate hypotheses, endpoints, and sample sizes for future investigations.