Effects of felodipine on pacing-induced angina pectoris.

We determined hemodynamics and myocardial lactate extraction in 11 patients with severe coronary disease after 0.010 (D1), 0.015 (D2), and 0.025 nmol/min (D3) of the arteriolar dilator felodipine during pacing-induced angina pectoris. Plasma concentrations of felodipine after the 3 doses were 12 (5), 25 (6) and 43 (8) nmol/ L, respectively. At corresponding pacing rates, mean blood pressure fell from 126 (24) to 90 (15) mm Hg at D3 (p less than 0.01) and pulmonary capillary wedge pressure was reduced from 14 (10) to 9 (8) mm Hg (p less than 0.05). Cardiac output increased at all three doses (p less than 0.01). The reduction of systemic vascular resistance at D3 was 49% (p less than 0.01) and of coronary vascular resistance 35% (p less than 0.05). At D1, there was no change in lactate extraction, while 8/10 lactate producers improved at D2 and D3. ST depression was diminished at all three doses (p less than 0.05) at the control pacing rate. During maximal pacing rate at D3, the myocardial oxygen consumption was 14% above control level (N.S.). Thus, felodipine was beneficial in most patients at higher dosage. Ventricular unloading and improved coronary perfusion might explain some of these positive effects.