Left ventricular function and volume during supine exercise in subjects with coronary artery disease.

Left ventricular function and volume changes during supine isotonic exercise were assessed in 32 patients with coronary artery disease (CAD) and 12 normal subjects by electrocardiographically gated blood pool cardiac scintigraphy. Ejection fraction (EF) in normal subjects was 49 +/- 10% at rest, 54 +/- 10% during intermediate exercise (P less than 0.05 vs. rest), and 62 +/- 14% during maximal exercise (P less than 0.01 vs. rest). In patients with CAD the resting EF was 42 +/- 14%, 43 +/- 23% at intermediate exercise (P = nonsignificant vs. rest) and 36 +/- 11% at maximal exercise (P less than 0.01 vs. rest). Changes of average and maximal ejection rates from rest to exercise were similar to those of EF but had a lesser degree of statistical significance. End-diastolic volume index (EDVI) in patients with CAD, at intermediate exercise was equal to that at rest, but it increased during maximal exercise (P less than 0.01). In normal subjects EDVI did not change with exercise. Thus, during supine exercise the Frank-Starling mechanism is apparent in patients with CAD but not in normal subjects. Analysis of EF response to exercise is a highly sensitive technique to detect CAD provided that adequate exercise is achieved.