Cardiovascular mechanisms of functional aerobic impairment in patients with coronary heart disease.

rest and at four levels of submaximal exercise on a bicycle ergometer, cardiac output (Q), using the direct Fick principle, heart rate (HR), mean systemic and pulmonary arterial pressures, and arterial-mixed venous oxygen difference (A-V 02 D) were evaluated in relation to relative aerobic requirement (% V0,11J). Q was highly correlated with V02, and both the level and the rate of change of Q were lower in patients with angina at all submaximal workloads. Stroke volume (SV) and HR were significantly restricted at the higher workloads. Although peripheral resist-