Reprodictioii 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 stan-dardized, 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 per-formed two treadmill tests after pulmonary and brachial arterial catheterization. The study de-sign allowed evaluation of the effects of 0.005 mg/kg of ouabain at rest-both supine and stand-ing-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 sys-temic 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. Additional Indexing Words: Ischemic (coronary) heart disease Arterial-mixed venous oxygen differenc