Effects of Nitroglycerin on Regional Myocardial Blood Flow in Coronary Artery Disease

Lawrence D. Horwitz; Richard Gorlin; Warren J. Taylor; Harvey G. Kemp

doi:10.1172/JCI106645

Effects of Nitroglycerin on Regional Myocardial Blood Flow in Coronary Artery Disease

Lawrence D. Horwitz, Richard Gorlin, Warren J. Taylor, and Harvey G. Kemp

Published August 1, 1971 - More info

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Abstract

Regional myocardial blood flow before and after sublingual nitroglycerin was measured in 10 patients with coronary artery disease. During thoracotomy, ¹³³Xe was injected directly into the subepicardium in diseased regions of the anterior left ventricular wall, and washout rates were recorded with a scintillation counter. All disappearance curves were closely approximated by two exponential decays analyzed as two parallel flow systems by the compartmental method. The appearance of a double exponential decay pattern in diseased regions suggests that the slow phase was associated with collateral blood flow, although nonhomogeneous myocardium-to-blood partition coefficients for xenon cannot be excluded. Nitroglycerin increased the rapid phase flow in 9 of 10 patients and the slow flow in 7 of 10 patients. Average flow increased in 9 of the 10 patients (P < 0.01). Mean rapid phase flow in the control state was 110 ml/100 g per min and after nitroglycerin increased to 132 ml/100 g per min (P < 0.01); slow phase flow increased from 12 ml/100 g per min to 15 ml/100 g per min (P < 0.05). It is concluded that, under these conditions, nitroglycerin improves perfusion in regions of diseased myocardium in patients with coronary artery disease.