[Effects of nicardipine on regional coronary deficit and the ST segment of the healthy and ischemic myocardium in dogs].

The effects of nicardipine, a phenyldihydropyridine calcium-channel antagonist agent, have been investigated on regional blood flow and epicardial ST-segment elevation in the nonischemic and ischemic myocardial zones after either intermittent, or permanent coronary artery occlusion in dogs. Whichever the experimental model used, nicardipine reduced heart rate and arterial blood pressure and increased regional myocardial blood flows (50 to 100% of control flow values). All these effects were dose-dependent. During intermittent coronary occlusion (a model that mimics angina pectoris), the nicardipine-induced myocardial vasodilation was homogeneous between the endocardium and the epicardium of the ischemic and nonischemic zones. During permanent coronary occlusion (a model that mimics myocardial infarction), the nicardipine-induced myocardial vasodilation mainly developed within the endocardium of the ischemic zone, leading thus to a beneficial transmural blood flow redistribution in that zone. Finally, and whichever the experimental model used, nicardipine did not reduce the ischemic injury as assessed by epicardial ST-segment elevation.