MYOCARDIAL CONTRAST ECHOCARDIOGRAPHY IN ACUTE MYOCARDIAL-INFARCTION -PATHOPHYSIOLOGICAL BACKGROUND AND CLINICAL-APPLICATIONS

Myocardial contrast echocardiography is a technique used in experiment al and clinical settings in order to visualize the pattern of intramyo cardial perfusion. In the acute phase of myocardial infarction, region al absence of flow during myocardial contrast echocardiography delinea tes the area at risk of necrosis, while the definitive non-perfused ar ea expresses infarct size. Reopening the infarct-related artery, which may be achieved spontaneously by thrombolysis or percutaneous translu minal coronary angioplasty, is not a reliable indicator of intramyocar dial reperfusion. If myocardial ischaemia due to coronary occlusion ha s been sufficiently prolonged and severe, not only myocyte viability, but also microvascular integrity is lost. Myocardial contrast echocard iography, using intracoronary injection of sonicated contrast medium, gives information about microvascular integrity and the effective pres ence of intramyocardial reflow. Anatomical integrity of microvasculatu re does not necessarily imply preserved function, and thus the microve ssel vasodilating reserve may also be impaired. Myocardial contrast ec hocardiography has the potential to assess alterations in microvascula r Function, showing, in the myocardial area with reduced coronary rese rve, a relatively reduced increase in echocontrast signal intensity wh en an intravenous vasodilator agent is administered.