Importance of flow/metabolism studies in predicting late recovery of function following reperfusion in patients with acute myocardial infarction.

Abstract

Positron emission tomographic imaging is known to be a reliable indicator of viable myocardium in chronic heart disease. Its value in acute myocardial infarction has not been studied extensively. Sixty-two patients receiving thrombolytic therapy were studied. Myocardial tissue flow and metabolism were measured at 5 days and 3 months. Recovery of left ventricular function was investigated with echocardiography or radionuclide ventriculography. In eight patients, normal flow was found in the infarct area at 5 days with no significant changes in flow, metabolism or function over the next 3 months. In 54 patients, impaired regional myocardial blood flow in the infarct zone was observed at 5 days. In 39 patients, there was a matching positron emission tomographic pattern, while in 15 the pattern was mismatched. None of the patients with a TIMI flow grade < 3 revealed recovery of left ventricular function. In seven out of 11 patients with TIMI 3 flow and a mismatching pattern, additional angioplasty was performed with functional improvement in six. Recovery of ventricular function is exclusively found in patients with a TIMI flow grade 3. Patients with a positron emission tomographic mismatching pattern reveal functional recovery only after subsequent angioplasty.