Calcium Antagonists and Myocardial Microperfusion

Recent studies have improved our understanding of the beneficial actions of calcium antagonists on myocardial microcirculation and metabolism. The effect of calcium antagonists on the microcirculation of the left ventricular rat myocardium was studied using in vivo microscopic techniques. Intravenous verapamil 0.3 mg/kg and nifedipine 75 µg/kg produced a 15 to 18% increase in the diameter of larger A1 and A2 coronary arterioles (range 31 to 300µm); diameters of terminal (A4) arterioles and capillaries did not change significantly.