Twelve male patients age 36-66, 8 on clinical doses of beta blocker, with old transmural myocardial infarction underwent rest and matched workload exercise before and 30 min after 20 mg sublingual nifedipine during cardiac catheterization. For the group, resting heart rate, aortic pressure, pulmonary wedge pressure, systemic vascular resistance, cardiac index, and left ventricular ejection fraction were normal. Exercise duration was 12.5 +/- 1.5 min. Comparing exercise before and after nifedipine, heart rate, cardiac index, and mean velocity circumferential fiber shortening increased, while mean aortic pressure, systemic vascular resistance, pulmonary wedge pressure, right atrial pressure, left ventricular end-diastolic volume and left ventricular end-systolic volume decreased with no significant change in double product, pulmonary arteriolar resistance and left ventricular ejection fraction. Therefore, for the range of left ventricular dysfunction in this study group and with 8 patients concurrently on beta blocker, nifedipine 20 mg s.l. produced significant improvement in hemodynamics at rest and exercise.