Reproduction of maximal exercise performance in patients with angina pectoris despite ouabain treatment.

Eight patients with a diagnosis of atherosclerotic heart disease and a history of typical angina pectoris, uncomplicated by cardiac dilatation or heart failure, were studied by means of standardized, symptom-limited treadmill exercise test. Repeatability of such testing was determined during two control tests 1-1.5 hours apart. From two to six days later, the same patients performed two treadmill tests after pulmonary and brachial arterial catheterization. The study design allowed evaluation of the effects of 0.005 mg/kg of ouabain at rest-both supine and standing-and during submaximal and maximal exercise. Measurements were made of oxygen uptake, arterial-mixed venous oxygen difference, heart rate, systemic arterial pressures and pulmonary arterial mean pressure. The ratio of mean systemic to mean pulmonary arterial pressure relative to cardiac output indicated that acute left ventricular dysfunction limited aerobic work. Treatment with ouabain did not significantly change performance or capacity and angina was not alleviated.