Fourth universal definition of myocardial infarction

The Fourth Universal Definition of Myocardial infarction proposes that the term acute myocardial infarction (AMI) should be used only when there is acute myocardial damage with clinical evidence of acute myocardial ischemia. The diagnosis of AMI requires elevation or drop in troponin values and the presence of at least one of the following criteria: (1) symptoms of acute myocardial isquemia; (2) new ischemic electrocardiographic (EKG) findings; (3) development of new abnormal Q waves; (4) imaging evidence of loss of viable myocardium or abnormal motion of any of the walls due to ischemic cause; or (5) identification of a coronary thrombus on angiography. Should this not be the case, then the proposal is to refer only to myocardial damage. Perioperative AMI is one of the most important complications and one of the major causes of morbidity andmortality in patients undergoing non-cardiac surgery; peak incidence is found during the postoperative period. Although more infrequent, intraoperative AMI is associated with greater morbidity and a very high risk of mortality. Close to 230 million major surgical procedures are performed worldwide every year, posing a huge challenge to anesthetists given the countless complications that may occur in the operating room; of these cases, more than 10 million experience perioperative cardiac events. Diagnosis and management of AMI during surgery are not widely described in the literature, considering that intraoperative ST-segment changes are extremely rare. Timely detection and treatment may ensure better survival prognosis in patients suffering this event, which is associated with extremely highmorbidity andmortality in all cases. With the new AMI classification, there are 5 pathophysiological causes implicated in the development of this event. Type 1 AMI is caused by atherothrombotic coronary heart disease and it is normally triggered by rupture or erosion of the atherosclerotic plaque; type 2 AMI is due to an imbalance between oxygen supply and consumption; type 3 AMI occurs in patients with typical AMI symptoms but who die before troponin determination or even before troponin elevation. There is also a type 4 and a type 5 AMI, associated with cardiac surgery treatments. There is debate regarding the pathophysiological mechanism of perioperative AMI. This period is known to be characterized by increased myocardial metabolic