Infarct sizing with technetium-99m stannous pyrophosphate scintigraphy in dogs and man; relationship between scintigraphic and praecordial mapping estimates of infarct size in patients.

The present study was performed in order to evaluate the ability of technetium-99m stannous pyrophosphate (99mTc-PYP) myocardial scintigrams to size infarcts in experimental animals and man. In 10 dogs with proximal left anterior descending coronary artery occlusion and acute anterior myocardial infarcts, there was a significant correlation between scintigraphic infarct size and histological infarct weight (P less than 0.01). In 25 patients with acute anterior or anterolateral myocardial infarcts, there was a significant correlation between relatively large infarct size determined scintigraphically and the acute development of left ventricular failure. There was some overlap, however, in 99mTc-PYP scintigraphic infarct size between patients who did and did not develop left ventricular failure with infarction. Presumably this is explained by some patients having had earlier myocardial damage and thus developing left ventricular failure with relatively small new infarcts. There was also a statistically significant, but weak, correlation in patients between scintigraphic infarct size and precordial ST segment mapping including peak ST segment elevation (P less than 0.05) and the number of praecordial sites with ST segment elevation equal to or greater than 2 mm (P less than 0.01). The data suggest that 99mTc-PYP scintigrams and praecordial mapping measure some similar but some dissimilar aspects of infarct size in patients, and that 99mTc-PYP scintigraphy does size acute anterior and anterolateral infarcts in experimental animals and patients.