An exercise hemodynamic comparison of verapamil, diltiazem, and amlodipine in coronary artery disease

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Abstract
A prospective, randomized study compared the effects of equivalent intravenous doses of three slow calciumchannel blockers (verapamil, diltiazem, and amlodipine) on rest and exercise haemodynamics in 30 ischemic heart disease patients. Following a stable control period during which rest and exercise (supine bicycle) hemodynamics were assessed, equivalent hypotensive doses of each compound were administered over 20 minutes and rest/exercise parameters were assessed 10 minutes later. At rest all agents similarly reduced systemic blood pressure; the fall in systemic vascular resistance and the increase in cardiac indices was ranked: amlodipine > diltiazem > verapamil. The heart rate increase for amlodopine differed from verapamil and diltiazem (+19.4% vs. +1.5% vs. −7%; p<0.01). On exercise, similarly greater falls in the systemic vascular resistance index followed amlodipine, compared with verapamil and diltiazem (p<0.05). Only amlodipine significantly reduced the exercise pulmonary artery occlusion pressure (PAOP). Exercise cardiac stroke volume improved after diltiazem and amlodipine. In terms of cardiac performance, both amlodipine and diltiazem produced an improvement, whereas verapamil depressed cardiac pumping activity. Thus, hemodynamic differences between slow-calcium-channel blocking drugs may be demonstrated in humans. These differences would be compatible with a predominant peripheral vascular site of action for amlodipine, in contrast with mixed cardiac and peripheral sites for diltiazem and verapamil.