Effect of intravenous and intracoronary nitroglycerin on left ventricular wall motion and perfusion in patients with coronary artery disease

Left ventricular anterior wall motion and distribution of coronary perfusion were assessed by contrast cineangiography and the dual isotope-labeled intracoronary microsphere technique before and after intravenous or intracoronary administration of nitroglycerin in 30 patients with significant left anterior descending coronary artery disease and resting anterior wall asynergy. Perfusion was measured in 11 additional control patients before and after administration of saline solution. Reversible asynergy was observed in 6 (43 percent) of 14 patients after systemic (intravenous) nitroglycerin and in 7 (44 percent) of 16 patients after intracoronary nitroglycerin. Significant reductions of blood pressure and improved wall motion were noted in both groups receiving nitroglycerin, suggesting afterload reduction as the common mechanism. There was also a small increase in end-diastolic volume index in patients with reversible asynergy after intracoronary administration of nitroglycerin, but no significant trends in preload change after intravenous administration. Ejection fraction increased significantly in patients with reversible asynergy after both intravenous and intracoronary nitroglycerin. Both intravenous and intracoronary nitroglycerin resulted in significant increases and decreases in distribution of coronary perfusion to the anterior wall. However, these changes were randomly distributed and improved perfusion did not consistently occur with improved wall motion.In conclusion, both intravenous and intracoronary nitroglycerin may reverse wall motion asynergy and produce both favorable and unfavorable changes in perfusion in patients with coronary disease. The common mechanism in improving wall motion with either intravenous or intracoronary nitroglycerin was afterload reduction, suggesting that the systemic effects of nitroglycerin are the most important in reversing asynergy.