Left ventricular response to exercise in coronary artery disease: relation to myocardial ischaemia and effects of nifedipine.

To assess the relationship between left ventricular (LV) response to exercise and myocardial ischaemia, 40 patients with coronary artery disease (CAD) and 17 control subjects underwent radionuclide ventriculography at rest and during semiupright exercise. In 14 of the 40 patients with CAD, radionuclide exercise studies were repeated 20 min after 20 mg of sublingual nifedipine. Patients with CAD had increases in both LV end-diastolic and end-systolic volumes and no change in ejection fraction during exercise. End-systolic volume increased and ejection fraction decreased significantly more in patients with multivessel disease, exercise-induced angina and/or ischaemic ST segment depression. Nifedipine reduced angina and ST-segment depression during exercise, attenuated exercise-induced increase in end-diastolic and end-systolic volumes and improved ejection fraction. This study suggests that in patients with CAD, the response of LV volumes and ejection fraction to exercise is related to the degree of exercise-induced myocardial ischaemia and nifedipine improves exercise LV performance.