Classification of myocardial infarction: frequency and features of type 2 myocardial infarction

Am J Med. 2013 Sep;126(9):789-97. doi: 10.1016/j.amjmed.2013.02.029. Epub 2013 Jul 12.


Background: The classification of myocardial infarction into 5 types was introduced in 2007 as an important component of the universal definition. In contrast to the plaque rupture-related type 1 myocardial infarction, type 2 myocardial infarction is considered to be caused by an imbalance between demand and supply of oxygen in the myocardium. However, no specific criteria for type 2 myocardial infarction have been established.

Methods: We prospectively studied unselected hospital patients who had cardiac troponin I measured on clinical indication. The diagnosis and classification of myocardial infarction were established, and the frequency and features of type 2 myocardial infarction were investigated by use of novel developed criteria.

Results: From January 2010 to January 2011, a total of 7230 consecutive patients who had cardiac troponin I measured were evaluated, and 4499 patients qualified for inclusion. The diagnosis of myocardial infarction was established in 553 patients, of whom 386 (72%) had a type 1 myocardial infarction and 144 (26%) had a type 2 myocardial infarction. Patients in the group with type 2 myocardial infarction were older and more likely to be female, and had more comorbidities. The proportion of patients without significant coronary artery disease was higher in those with type 2 myocardial infarction (45%) than in those with type 1 myocardial infarction (12%) (P < .001). Tachyarrhythmias, anemia, and respiratory failure were the most prevalent mechanisms causing type 2 myocardial infarction.

Conclusions: In a cohort of patients with myocardial infarction who were admitted consecutively through 1 year, the category of type 2 myocardial infarction comprised one fourth when diagnosed by the use of newly developed criteria. Approximately half of patients with type 2 myocardial infarction had no significant coronary artery disease.

Keywords: Troponin; Type 2 myocardial infarction; Universal definition of myocardial infarction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Chi-Square Distribution
  • Female
  • Humans
  • Male
  • Myocardial Infarction / blood
  • Myocardial Infarction / classification*
  • Prospective Studies
  • Statistics, Nonparametric
  • Troponin I / blood


  • Troponin I