Pharmacologic Effects of a Nitrate Coronary Vasodilator on Cardiac Perfusion and Function,Measured Semiquantitatively

Abstract

The effects of a nitrate coronary vasodilator, Pentaerythritol Tetranitrate (Peritrate®), on perfusion and function of ischemic heart muscle were studied in six patients. Coronary angiograms were performed on all subjects, and a high degree of triple-vessel disease was present in all. Our studies were performed semiquantitatively by means of an image-processing computer [A²] and a gamma cammera. Perfusion of the myocardium was determined by thallium²⁰¹ imaging after exercise. Selected areas of ischemic myocardium were chosen for study. Function of the myocardium was determined by technetium99 imaging with determination of total and segmental wall motion after exercise. A single-blind study with a placebo was performed. Significant increases in perfusion and function of ischemic areas occurred with Peritrate. For the perfusion studies for each patient observed, the myocardium was divided into four segments, A-B, B-C, C-D, and D-A. The two segments that had the poorest perfusion were chosen for study for each patient. For the function studies, the myocardium was again divided into the same four segments, A-B, B-C, C-D, and D-A. Two segments that were deficient in wall motion were chosen for each patient. In the perfusion study, of the twelve segments chosen from the six patients (two segments per patient) and in the function study, of the twelve segments chosen from the six patients (two segments per patient), nine segments of the perfusion study were similar to nine segments of the function study. An increase of perfusion and wall motion occurred with Peritrate in 8 out of 9 segments of similarity.