ICD-10 code for heart attack

The ICD-10-CM code for heart attack is I21.9 (Acute myocardial infarction, unspecified). The official index lists 12 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on I21.9.

It is also searched as MI, myocardial infarction.

Within I21, choose I21.9 (unspecified) only when documentation doesn't support a more specific option: ST elevation (STEMI) myocardial infarction of anterior wall (I21.0), ST elevation (STEMI) myocardial infarction of inferior wall (I21.1), ST elevation (STEMI) myocardial infarction of other sites (I21.2), ST elevation (STEMI) myocardial infarction of unspecified site (I21.3), Non-ST elevation (NSTEMI) myocardial infarction (I21.4), other type of myocardial infarction (I21.A) and myocardial infarction with coronary microvascular dysfunction (I21.B).

Use an additional code, if applicable, to identify: exposure to environmental tobacco smoke (Z77.22), history of tobacco dependence (Z87.891), occupational exposure to environmental tobacco smoke (Z57.31), status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility (Z92.82), tobacco dependence (F17.-) and 1 more.

As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" MS-DRG of its family, unless the principal diagnosis excludes it.