Systemic and Coronary Hemodynamic Effects of Diazepam in Patients with Normal and Diseased Coronary Arteries

Abstract

In 12 patients with significant coronary artery disease (group I) and in eight patients with normal coronary arteries (group II), 5 to 8.5 mg of diazepam was given intravenously before coronary angiography. Adequate sedation was obtained in 17 patients. Hypoventilation occurred in all patients but was without clinical correlate. Coronary and cardiovascular effects were assessed before as well as 10 and 20 min after diazepam. Heart rate was unchanged and aortic pressure (AP) decreased significantly ( P < 0.01) in most patients. Cardiac index decreased only in patients of group II ( P < 0.01). Of particular interest was a constant fall in left ventricular end-diastolic pressure (LVEDP) in both groups, ( P < 0.01) and ( P < 0.05) at 10 and 20 min respectively in group I and ( P < 0.01) at 10 and 20 min in group II. Tension-time index and myocardial oxygen consumption (MVO 2 ) were also significantly decreased ( P < 0.05) after diazepam in both groups. Since neither coronary blood flow nor coronary vascular resistance were modified by diazepam, the fall in LVEDP could be due to a decrease in AP (afterload) and/or in venous return (preload). The combination of these effects could reduce intra-cavitary volume, myocardial wall tension and left ventricular MVO 2 . Our data therefore suggest that, in addition to its central sedative effects, diazepam also has a nitroglycerin-like action on the coronary and systemic circulation.