Effects of Short-Term Intravenous Administration of Diltiazem on Left Ventricular Function and Coronary Hemodynamics in Patients with Coronary Artery Disease

Summary: The hemodynamic effects of diltiazem were investigated in 15 patients with suspected coronary artery disease undergoing routine cardiac catheterization. Diltiazem was given in a high dose of 500 μg/kg over a period of 5 min and measurements made before and after drug administration during spontaneous heart rate and during matched atrial pacing. Spontaneous heart rate did not change (−5%; NS). Left ventricular (LV) systolic pressure decreased 24% (p < 10−6) and LV end-diastolic pressure (LVEDP) did not change (−5%; NS). During coronary blood flow measurement, mean aortic pressure decreased 30% (p < 10−6) as global (coronary sinus) and regional (great cardiac vein) coronary vascular resistance diminished with no change in coronary blood flow. Myocardial oxygen consumption decreased 19% (p < 0.02). During matched pacing, although no change occurred in calculated systolic isovolumic indexes of contractility, end-systolic pressure–volume index decreased 15% (p < 0.05). The time constant of isovolumic relaxation assessed by a biexponential model decreased. No net change occurred in either global or regional wall motion. In summary, high-dose diltiazem was administrated safely to patients with coronary artery disease. It is concluded that, at this dose, diltiazem acted as a peripheral and coronary vasodilator. Hemodynamic changes consistent with a direct negative inotropic and chronotropic effect of the drug were observed. Myocardial oxygen consumption decreased with no change in coronary blood flow.