Acute Hemodynamic Effects of Nifedipine During Supine Exercise in Patients with Prior Myocardial Infarction

Twelve male patients age 36-66, 8 on clinical doses of beta blocker, with old transmural myocardial infarction underwent rest and matched workload exer cise before and 30 min after 20 mg sublingual nifedipine during cardiac cathe terization. For the group, resting heart rate, aortic pressure, pulmonary wedge pressure, systemic vascular resistance, cardiac index, and left ventricular ejec tion fraction were normal. Exercise duration was 12.5 ± 1.5 min. Comparing exercise before and after nifedipine, heart rate, cardiac index, and mean veloc ity circumferential fiber shortening increased, while mean aortic pressure, sys temic vascular resistance, pulmonary wedge pressure, right atrial pressure, left ventricular end-diastolic volume and left ventricular end-systolic volume de creased with no significant change in double product, pulmonary arteriolar re sistance 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 hemo dynamics at rest and exercise.