Clinicopathologic study of persistently positive technetium-99m stannous pyrophosphate myocardial scintigrams and myocytolytic degeneration after myocardial infarction

In a select series of 46 patients studied by serial myocardial scintigraphy, 19 (41%) retained persistent, usually low grade (2+) positive technetium-99m stannous pyrophosphate (/sup 99m/Tc-PYP) myocardial scintigrams for at least 3 months after acute myocardial infarction. The one major difference between patients with positive and negative postinfarct /sup 99m/Tc-PYP myocardial scintigrams was a more symptomatic postinfarct course in the former group, characterized by severe angina pectoris in 16 of 19 patients and by severe congestive heart failure with angina in three patients. In a separate clinicopathologic series of seven patients, persistently positive /sup 99m/Tc-PYP myocardial activity was associated with prominent myocytolytic degeneration involving muscle cells which had survived initial episodes of infarction in 5 patients (three with ventricular aneurysms) and with extensive myocardial fibrosis in one patient with recurrent angina pectoris. One patient with a negative postinfarct /sup 99m/Tc-PYP myocardial scintigram had transmural fibrosis without residual myocardium in a resected ventricular aneurysm. It is concluded that a persistently positive /sup 99m/Tc-PYP myocardial scintigram frequently correlates with progressive myocardial damage and muscle loss and that this scintigraphic finding may be an important prognostic indicator of a complicated and symptomatic postinfarct clinical course.