Addition of nifedipine to maximal nitrate and beta-adrenoreceptor blocker therapy in coronary artery disease

Abstract

The effects of oral nifedipine on left ventricular (LV) diastolic function were assessed in 14 patients with coronary artery disease (CAD) who had symptoms despite therapy with β-adrenoreceptor blocking drugs and nitrates. Rest and exercise gated radionuclide ventriculography was performed before and a mean of 13 days after the addition of oral nifedipine (80 to 120 mg/day) to baseline medication. Ejection fraction did not increase in any patient during exercise. The addition of nifedipine slightly improved the LV ejection fraction response to exercise (control, 49 ± 8% rest vs 44 ± 9% exercise; nifedipine, 47 ± 6% vs 48 ± 8%). With nifedipine treatment, diastolic function improved, with a decrease in the time to peak filling rate (PFR) at rest (from 174 ± 34 to 152 ± 31 ms, p < 0.005) and an increase in PFR with exercise (from 2.5 ± 0.6 to 3.4 ± 0.7 end-diastolic volume/s, p < 0.0005). Using the ratio of PFR/peak ejection rate as a variable, preferential improvement of diastolic over systolic function occurred during exercise (1.03 ± 0.29 baseline vs 1.4 ± 0.43 with nifedipine, p < 0.01). Duration of exercise increased by a mean of 21% with nifedipine (from 454 ± 150 to 550 ± 159 seconds, p < 0.005); all 14 patients were limited by angina pectoris at baseline, whereas only 5 patients were limited by angina pectoris after nifedipine treatment. This study shows that global LV diastolic function is improved by oral nifedipine treatment both at rest and during exercise in patients on maximally tolerated doses of β-adrenoreceptor blockers and nitrates, and is associated with improvement of symptoms and exercise tolerances.