[Effect of nitroglycerin on the extent of myocardial infarction]

Myocardial infarction in rabbits was caused by ligation of the anterior descending artery. Nitroglycerin was given intravenously (100 micrograms/min) 120--180 min after the operation. In both control and experimental groups, precordial ECG maps were recorded 30, 120, 180 and 360 min after the operation. 7 days after the operation the size of myocardial infarction was measured by planimetry. Rapid and statistically significant dynamics of ECG was observed in the control group under the effect of nitroglycerin. Bradycardia under the effect of nitroglycerin was recorded in the experimental group but was not seen in the control group or in the complementary one where nitroglycerin was given to anesthetized but non-operated animals. Therefore bradycardia under the effect of nitroglycerin was observed only in animals with acute myocardial infarction. Planimetry demonstrated a statistically significant reduction of the area of necrosis in the experimental group (by 41.2%) as compared with the control one.