Myocardial infarction Difinition

Fourth Universal Definition Separates MI From Myocardial Injury

Marlene Busko

August 26, 2018

The document defines the five subtypes of myocardial infarction as:

• Type 1: Due to an atherosclerotic plaque rupture with subsequent coronary arterial thrombosis; patients can have an ST-elevation or a non-ST elevation myocardial infarction and are usually treated with antiplatelet medication and stenting of the culprit lesion in the coronary artery;
• Type 2: Due to ischemia (oxygen deprivation) without any plaque disruption; for example, a patient may have hypotension (decreased myocardial oxygen supply) or a tachyarrhythmia (increased myocardial oxygen demand);
• Type 3: Classic (such as typical ST elevation; electrocardiogram) but no troponin blood test result;
• Type 4: In the setting of a percutaneous coronary intervention in the catheterization laboratory; and
• Type 5: At the time of coronary bypass surgery.

"You can have myocardial injury and the release of troponin" that can be detected by high-sensitivity troponin assays if you have kidney disease or even if you are an athlete (eg, a runner), which is "certainly not myocardial infarction," Thygesen stressed. Other situations that can cause myocardial injury and a rise in troponin include Infection, sepsis, and heart surgery.