Effect of the calcium antagonists foridon and nifedipine on systemic hemodynamics and myocardial blood flow in dogs with acute myocardial ischemia

: Systemic haemodynamic and myocardial blood flow effects of ryodipine and nifedipine have been studied during acute transitory coronary occlusion in the open-chest anesthetized dogs. Acute ischemia has been done by occlusion of left anterior descending coronary artery for 5 min. Cardiac output and blood flows in the ischemic, lateral border and intact areas of the myocardium were defined with 15 mcm plastic radiolabelled microspheres. Drugs were administered intravenously in equihypotensive doses. Both drugs prevented fall of cardiac index during occlusion, decreased arterial pressure and total peripheral resistance but heart rate remained unchanged. Ryodipine as well as nifedipine considerably increased blood flow (42 +/- 15% and 85 +/- 23%, respectively, P less than 0.05) in the intact zones of the left ventricle, but they did not affect the blood flow in the ischemic zone.