The Effect of Calcium Antagonist, Diltiazem, on the Relation of Coronary Blood Flow to Regional Myocardial Function

To study the effect of diltiazem (0.3mg/kg) on the relation of coronary blood flow (CBF) to regional myocardial function, left ventricular (LV) pressure, LV wall thickening (%W) by sonomicrometry, and CBF by electromagnetic flowmeter, were measured in 10 anesthetized dogs. CBF was reduced by coronary occluder to induce several degrees of coronary stenosis. The procedures were accompanied by various degrees of regional dysfunction. CBFs during systole (S) and diastole (D) were calculated and D/S ratio was obtained. After diltiazem infusion, heart rate (HR) decreased significantly, but other hemodynamic parameters were not changed CBF-%W relation curve was upward convex, and was shifted upward after diltiazem. D/S ratio increased at mild to moderate reduction of CBF after diltiazem. Thus, diltiazem improved the regional myocardial function by decreasing HR and increasing D/S ratio, which may improve the subendocardial perfusion.