Left Ventricular Excursions and Velocities During Coronary Arterial Ligation. Effects of Nitroglycerin Infusion in an Experimental Model

Abstract

To determine the effects of intravenous nitroglycerin on the velocities and excursions of the acutely ischemic myocardium, 20 open-chest dogs were stud ied by use of ultrasound. In 10 dogs with acute septal ischemia, the posterior wall excursion during contraction (B-C excursion), the mean systolic posterior wall velocity, and the posterior wall excursion remained unaltered. Nitroglyc erin, however, increased all these parameters (P < 0.01). In 10 dogs with acute posterior wall ischemia the B-C excursion (aneurysmal bulging) increased (P < 0.01), but the mean systolic posterior wall velocity and posterior wall excursion decreased (P < 0.01). Nitroglycerin increased even more the aneurysmal bulg ing (P < 0.01) and the other parameters (P < 0.01). Increased regional blood flow, reduced afterload, and mechanical pulling of the ischemic myocardium seem to be a possible mechanism. The measurements were obtained using the recently described method of the specific points.