Fourth universal definition of myocardial infarction (2018)

... ... ... ... In the late 19th century, post-mortem examinations demonstrated a possible relationship between thrombotic occlusion of a coronary artery and myocardial infarction (MI).1 However, it was not until the beginning of the 20th century that the first clinical descriptions appeared describing a connection between the formation of a thrombus in a coronary artery and its associated clinical features.2 , 3 Despite these landmark observations, considerable time elapsed before general clinical acceptance of this entity was achieved, in part due to one autopsy study that showed no thrombi in the coronary arteries of 31% of deceased patients with an MI.4 The clinical entity was referred to as coronary thrombosis, although use of the term ‘MI’ ultimately prevailed. Over the years, several different definitions of MI have been used, leading to controversy and confusion. Hence, a general and worldwide definition for MI was needed. This occurred for the first time in the 1950–70s, when working groups from the World Health Organization (WHO) established a primarily electrocardiographic (ECG)-based definition of MI intended for epidemiological use.5 The original description, with minor modifications, is still used in epidemiological surveys (Figure 1).6–8