Atrial pacing and exercise in the evaluation of patients with angina pectoris.

The anginal threshold was determined by atrial pacing in 23 patients with coronary artery disease. Twelve of the 23 subjects also performed supine exercise at progressive workloads until the onset of angina. Atrial pacing produced a fall in left ventricular stroke work index and left ventricular end-diastolic pressure (LVEDP); cardiac output increased, and, with the onset of angina, left ventricular dysfunction was sometimes evidenced, either by an increase in LVEDP or by an abnormal LVEDP in the postpacing period. In contrast, exercise consistently produced left ventricular dysfunction. The tension-time index at the onset of angina was similar whether the pain was induced