Two dimensional echocardiographic quantification of infarct size alteration by pharmacologic agents.

In 27 closed chest dogs left ventricular wall motion abnormalities assessed quantitatively with two dimensional echocardiography were used as a measure of myocardial infarct size, and the change in extent of segmental wall motion abnormalities due to drug intervention early after infarction was evaluated. The extent of wall motion abnormalities was measured with echocardiography before and at 20 and 40 minutes and 5 1/2 hours after coronary occlusion. Three subgroups of dogs received, respectively, an infusion of nitroglycerin, phenylephrine or saline solution. Infarct size was measured with technetium pyrophosphate scintigraphy of the excised left ventricle. The infarct size correlated well with the extent of wall motion abnormalities before death. Wall motion was initially similar among the three groups but was significantly improved after treatment with nitroglycerin (P less than 0.025), remained stable with continued saline infusion and worsened significantly (P less than 0.05) after treatment with phenylephrine. Two dimensional echocardiography can be used to quantify experimental canine myocardial infarction and assess the effect of nitroglycerin.