Left-ventricular angiography was performed in 28 patients after measuring ascending aortic and left ventricular pressures and during isometric exercise (hand grip, 0.3-0.4 kg/cm2 for 3 min). In 13 patients coronary blood flow was measured at rest and during hand-grip exercise by means of the argon method. Eight patients without heart disease served as controls. In 14 patients with coronary heart disease abnormal left-ventricular kinetics, demonstrated already at rest, got worse during hand-grip exercise. In five patients with normal left-ventricular angiograms at rest hypokinesia and dyskinesia occurred during isometric exercise. The coronary artery supplying the abnormal ventricular wall had a 50-75% decrease in diameter. One patients with isolated 25% stenosis had normal left-ventricular kinetics both at rest and on hand-grip exercise. In all patients coronary blood flow rose by 60-90% during isometric exercise. It iducing a significant rise in myocardial oxygen demand and increased coronary blood flow.