Myocardial viability. Open artery theory.
Left ventricular ejection fraction at rest is the most powerful predictor of death in survived patients after acute myocardial infarction (AMI). Areas of poor contractility after AMI are not always related to necrosis. Stunned and hibernating myocardium are areas of potentially reversible damage which can improve spontaneously or after intervention to re-establish coronary blood flow. Several techniques has been investigated to study myocardial viability. Positron emission tomography (PET) is the gold standard for that purpose. However PET scan is a very expensive technique not available in a lot of countries. Myocardial perfusion scintigraphy and stress echocardiography are the most attractive alternative strategies. With these techniques is possible to predict the outcome and to properly select such patients which can improve with revascularization. A close relationship between open coronary artery and left ventricular (LV) function after AMI is a very well addressed topic in some published trials. However, the most significant benefits are obtained when artery patency is achieved in few hours, with a strong flow and the patency is sustained. We can summarize the benefits of an open artery: time dependent benefits (the traditional sequence of events after early reperfusion with infarct size reduction and left ventricular function improvement) and time independent benefits (thrombolysis may improve healing of infarction; may prevent the infarct expansion; may perfuse areas of hibernating segments; may increase electrical stability; may improve collateral blood flow). The role of collateral blood flow after AMI and its influence on LV function preservation is an important topic poorly elucidated.(ABSTRACT TRUNCATED AT 250 WORDS)
Morais
J
J
Cardiology Department, University Hospital, Coimbra, Portugal.
D003097:Collateral Circulation / Q000187:drug effects; D003331:Coronary Vessels / Q000187:drug effects / Q000503:physiopathology*; D006801:Humans; D009203:Myocardial Infarction / Q000188:drug therapy / Q000401:mortality / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology*; D009336:Necrosis; D011379:Prognosis; D018570:Risk Assessment; D015912:Thrombolytic Therapy; D014022:Tissue Survival / Q000187:drug effects; D014654:Vascular Patency / Q000187:drug effects