In simple words: This code indicates a second heart attack within four weeks of a previous heart attack.

Subsequent ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction. Includes: acute myocardial infarction occurring within four weeks (28 days) of a previous acute myocardial infarction, regardless of site, cardiac infarction, coronary (artery) embolism, coronary (artery) occlusion, coronary (artery) rupture, coronary (artery) thrombosis, infarction of heart, myocardium, or ventricle, recurrent myocardial infarction, reinfarction of myocardium, rupture of heart, myocardium, or ventricle, subsequent type 1 myocardial infarction. Use 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.-), tobacco use (Z72.0). Excludes1: subsequent myocardial infarction, type 2 (I21.A1), subsequent myocardial infarction of other type (type 3) (type 4) (type 5) (I21.A9).

Example 1: A patient presents with chest pain and shortness of breath and is diagnosed with a STEMI. This is their second heart attack in three weeks., A patient experiences another NSTEMI a week after being discharged for a previous NSTEMI., 20 days after suffering a heart attack, a patient is readmitted with symptoms indicative of a recurrent myocardial infarction, confirmed by diagnostic tests.

Documentation should include the time frame between the two heart attacks, ECG findings, cardiac enzyme levels, and any other relevant diagnostic tests.