MYOCARDIAL VIABILITY - RESULTS OF MYOCARD IAL REVASCULARIZATION DURING THE ACUTE-PHASE OF MYOCARDIAL-INFARCTION

Complete coronary reperfusion after thrombolysis or primary angioplast y is associated with limitation of infarct size and conservation of le ft ventricular function. The area of viable myocardium recovers its fu nction secondarily. the amount of recovery being related to the precoc ity of reperfusion. Patients with a patent artery in tl-e acute stage do not all recover segmental contraction to the same extent. There are considerable discrepancies between coronary patency and myocardial pe rfusion. Myocardial perfusion, measured in the acute phase by myocardi al contrast echocardiography is the best predictor of preservation of function. This suggests that microvascular lesions are a sign of the e xtent and irreverisibility of myocardial damage. Modern treatment of i nfarction should not only restore coronary patency but also ensure eff ective myocardial reperfusion. The factors which determine recovery of ventricular function after reperfusion during the acute phase are, in addition to early and complete coronary recanalisation and effective myocardial reperfusion : short duration of ischaemia, small size of th e area at risk, collateral circulation, ability of the myocardium to w ithstand ischaemia, limitation of reperfusion il?jury. Other factors ( smoking, pre-infarction angina, the occluded artery or method of reper fusion) may play a role but the role of confounding factors is always difficult to exclude.