{"code":"I21.29","type":"code","title":"ST elevation (STEMI) myocardial infarction involving other sites","codeAlso":["the presence of hypertension (I10-I1A)"],"includes":["cardiac infarction","coronary (artery) embolism","coronary (artery) occlusion","coronary (artery) rupture","coronary (artery) thrombosis","infarction of heart, myocardium, or ventricle","myocardial infarction specified as acute or with a stated duration of 4 weeks (28 days) or less from onset"],"modern_v":"official26","codeFirst":[],"excludes1":[],"excludes2":["old myocardial infarction (I25.2)","postmyocardial infarction syndrome (I24.1)","subsequent type 1 myocardial infarction (I22.-)"],"isBillable":true,"fyEffectivity":{"fy2026":true,"fy2027":true,"billableFy2026":true,"billableFy2027":true},"sibling_codes":["I21","I21.0","I21.01","I21.02","I21.09","I21.1","I21.11","I21.19","I21.2","I21.21","I21.3","I21.4","I21.9","I21.A","I21.A1","I21.A9","I21.B"],"inclusionTerms":["Acute transmural myocardial infarction of other sites","Apical-lateral transmural (Q wave) infarction (acute)","Basal-lateral transmural (Q wave) infarction (acute)","High lateral transmural (Q wave) infarction (acute)","Lateral (wall) NOS transmural (Q wave) infarction (acute)","Posterior (true) transmural (Q wave) infarction (acute)","Posterobasal transmural (Q wave) infarction (acute)","Posterolateral transmural (Q wave) infarction (acute)","Posteroseptal transmural (Q wave) infarction (acute)","Septal transmural (Q wave) infarction (acute) NOS"],"sibling_titles":{"code":"I21.B","title":"Myocardial infarction with coronary microvascular dysfunction","isBillable":true},"useAdditionalCode":["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)"],"clinicalDefinition":"ST elevation (STEMI) myocardial infarction involving other sites is a billable ICD-10-CM diagnosis code (I21.29). Includes: cardiac infarction; coronary (artery) embolism; coronary (artery) occlusion; coronary (artery) rupture; coronary (artery) thrombosis; infarction of heart, myocardium, or ventricle; myocardial infarction specified as acute or with a stated duration of 4 weeks (28 days) or less from onset.","officialDefinition":"ST elevation (STEMI) myocardial infarction involving other sites is a billable ICD-10-CM diagnosis code (I21.29). Includes: cardiac infarction; coronary (artery) embolism; coronary (artery) occlusion; coronary (artery) rupture; coronary (artery) thrombosis; infarction of heart, myocardium, or ventricle; myocardial infarction specified as acute or with a stated duration of 4 weeks (28 days) or less from onset. Inclusion terms: Acute transmural myocardial infarction of other sites; Apical-lateral transmural (Q wave) infarction (acute); Basal-lateral transmural (Q wave) infarction (acute); High lateral transmural (Q wave) infarction (acute); Lateral (wall) NOS transmural (Q wave) infarction (acute); Posterior (true) transmural (Q wave) infarction (acute); Posterobasal transmural (Q wave) infarction (acute); Posterolateral transmural (Q wave) infarction (acute); Posteroseptal transmural (Q wave) infarction (acute); Septal transmural (Q wave) infarction (acute) NOS. Excludes2 (not included here): old myocardial infarction (I25.2); postmyocardial infarction syndrome (I24.1); subsequent type 1 myocardial infarction (I22.-). Use additional code: 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). Code also: the presence of hypertension (I10-I1A).","seventhCharacterInstructions":[],"workflowProtocols":[],"guidelines":{"whenToUse":[],"whenNotToUse":[],"commonBillingMistakes":[],"codeComparisons":[],"documentationChecklist":[]},"domainLandscape":{"summary":"Primary diagnostic domain and clinical landscape evaluation.","keyCategories":[],"diagnosticContinuum":"Progression continuum from acute presentation to resolution."},"children":[],"hierarchy":[],"relatedCodes":[],"relevantCPTCodes":[],"documentationTips":[],"caseStudies":[],"description":"","overview":"","noteProvenance":{"old myocardial infarction (I25.2)":"I21","postmyocardial infarction syndrome (I24.1)":"I21","subsequent type 1 myocardial infarction (I22.-)":"I21","code, if applicable, to identify:":"I21","exposure to environmental tobacco smoke (Z77.22)":"I21","history of tobacco dependence (Z87.891)":"I21","occupational exposure to environmental tobacco smoke (Z57.31)":"I21","status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility (Z92.82)":"I21","tobacco dependence (F17.-)":"I21","tobacco use (Z72.0)":"I21","cardiac infarction":"I21","coronary (artery) embolism":"I21","coronary (artery) occlusion":"I21","coronary (artery) rupture":"I21","coronary (artery) thrombosis":"I21","infarction of heart, myocardium, or ventricle":"I21","myocardial infarction specified as acute or with a stated duration of 4 weeks (28 days) or less from onset":"I21","Type 1 ST elevation myocardial infarction of other sites":"I21.2"},"hcc":{"mapped":true,"model":"CMS-HCC V28","paymentYear":"2026","categories":[{"hcc":"228","label":"Acute Myocardial Infarction","family":"Heart","suppresses":[{"hcc":"229","label":"Unstable Angina and Other Acute Ischemic Heart Disease"}]}],"otherModels":[{"model":"CMS-HCC V22","hcc":"86"},{"model":"RxHCC V08","hcc":"188"}]}}