Heart Groups Issue Third Universal Definition for Myocardial Infarction

The third universal definition for myocardial infarction has been issued by the American College of Cardiology, American Heart Association, European Society of Cardiology, and World Heart Federation. It establishes the level of troponin necessary to diagnose MI in various clinical situations (e.g., after cardiac and noncardiac procedures).

According to the definition, an MI diagnosis requires a cardiac troponin (I or T) level above the 99th percentile of a normal reference population, plus one or more of the following:

• symptoms of ischemia;

• new significant ST/T wave changes or left bundle branch block;

• pathologic Q waves on ECG;

• new loss of viable myocardium or regional wall motion abnormality, as observed on imaging;

• intracoronary thrombus diagnosed by angiography or autopsy.