Purpose of review
Myocardial infarction is a clinical diagnosis based on clinical presentation and laboratory tests. Clinicians have often defined myocardial infarction in different ways. In order to have a consistent universal definition, the four major international cardiac societies recently completed a consensus to define myocardial infarction in a universally acceptable manner.
Myocardial infarction is defined pathologically as myocyte necrosis due to prolonged ischemia. These conditions are met when there is a detection of a rise or fall or both of cardiac biomarkers, preferably troponins, with at least one value above the 99th percentile of the upper reference limit together with evidence of myocardial ischemia as recognized by at least one of the following: symptoms of ischemia, electrocardiogram changes of new ischemia, development of pathological Q waves, imaging evidence of new loss of viable myocardium or presence of new regional wall motion abnormality. Myocardial infarctions are divided into five types and can be spontaneous, secondary, or related to sudden cardiac death, percutaneous coronary intervention, or coronary artery bypass grafting.
The new universal definition with five types of myocardial infarction is based on troponin elevation together with ischemic symptoms, typical electrocardiogram changes, or imaging evidence of loss of viable myocardium.