Third Universal Definition of Myocardial Infarction


The following are 10 points to remember about this Expert Consensus Document:

1. Increasingly small amounts of myocardial necrosis can be detected by increasingly sensitive and myocardial tissue-specific biomarkers.

2. Myocardial necrosis may result from nonischemic mechanisms (e.g., heart failure) and should not be labeled as myocardial infarction (MI), but rather as myocardial injury.

3. The preferred biomarker for the detection of MI is cardiac troponin (cTn). An increased cTn is defined as a value exceeding the 99th percentile of a normal reference population (upper reference limit or URL).

4. MI is classified into five major types, based primarily on clinical and pathological differences. Type 1 MI is spontaneous MI and is related to atherosclerotic plaque disruption. In type 2 MI, a condition other than coronary artery disease contributes to an imbalance between myocardial oxygen supply and/or demand (e.g., coronary artery vasospasm or critical illness).

5. Those who suffer cardiac death with antecedent symptoms and electrocardiographic changes, but without available biomarker data, have had a type 3 MI.

6. MI types 4 and 5 are associated with revascularization procedures. Type 4a MI is related to percutaneous coronary intervention and is arbitrarily defined by elevation of cTn values to >5 times the 99th percentile URL in patients with normal baseline values or a rise of cTn values by >20% if the baseline values are elevated and are stable and falling. In addition, there should be supportive symptoms, electrocardiogram (ECG) changes, corroborative angiographic findings, and imaging with regional changes.

7. Type 5 MI is associated with coronary artery bypass grafting, and is arbitrarily defined by elevation of cardiac biomarkers to values 10 times the 99th percentile URL of cTn with supportive ECG, angiographic, or imaging.

8. Transcatheter aortic valve implantation (TAVI) may cause myocardial injury. In the absence of compelling evidence to inform the definition for MI following TAVI, it is reasonable to apply the criteria for type 5 MI.

9. Late gadolinium enhancement magnetic resonance imaging may distinguish between ischemic heart disease and other myocardial abnormalities.

10. Consistency to the definition of MI would inform a standardized approach for interpretation across different trials.

Keywords: Coronary Artery Disease, Myocardial Infarction, Myocardial Ischemia, Plaque, Atherosclerotic, Heart Injuries, Gadolinium, Troponin T, Electrocardiography, Heart Valve Prosthesis Implantation, Angioplasty, Magnetic Resonance Imaging, Percutaneous Coronary Intervention, Consensus, Coronary Vasospasm, Biomarkers, Coronary Angiography, Reference Standards, Heart Failure, Cardiovascular Diseases, Critical Illness, Oxygen, Coronary Artery Bypass

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