Effect of cinpropazide on ischemic myocardial acidosis in dogs

In dogs anesthetized with pentobarbital, the left anterior descending coronary artery (LAD) was occluded by an occluder so that the LAD flow could be set to about half the original flow (partial occlusion). Partial occlusion of the LAD continued for 90 min, and myocardial pH decreased by 0.71 pH unit 30 min after the start of partial occlusion. Cinpropazide, a coronary vasodilator, was injected intravenously 30 min after partial occlusion. Cinpropazide at the dose of 1 mg/kg, which increased LAD flow insignificantly in the nonischemic normal heart, attenuated the myocardial pH that has been reduced by partial occlusion, with a slight reduction in diastolic blood pressure. Restoration of myocardial [H+] 60 min after the injection of cinpropazide was 75.3%, and that of saline solution was 29.5%, indicating that cinpropazide restored the myocardial [H+] by 45.8% during ischemia. The effect of cinpropazide to increase myocardial pH was not observed in the dog with nonischemic heart, however. It is concluded that cinpropazide attenuates myocardial acidosis during ischemia.