2025 ICD-10-CM code I21.9
(Active) Effective Date: N/A Revision Date: N/A Circulatory System Diseases - Ischemic heart diseases Diseases of the circulatory system (I00-I99) Feed
Acute myocardial infarction, unspecified; a heart attack where the specific location of the infarction is unknown.
Modifiers may be applicable depending on the circumstances of the service and the payer’s specific requirements.
Medical necessity is established by the presence of symptoms consistent with acute myocardial infarction (AMI), confirmed by objective findings such as ECG changes and elevated cardiac biomarkers.Treatment is time-sensitive and requires immediate intervention to reduce morbidity and mortality.
The clinical responsibility includes diagnosis and management of the acute myocardial infarction, which may involve administering medications (such as thrombolytics, antiplatelet agents, anticoagulants, and pain relievers), performing cardiac catheterization, and providing ongoing cardiac care and monitoring.
In simple words: This code means a heart attack where doctors don't know exactly which part of the heart muscle was damaged. A heart attack happens when blood flow to the heart is blocked, usually by a clot or buildup of plaque in a heart artery, causing damage to the heart muscle.
This ICD-10-CM code, I21.9, signifies an acute myocardial infarction (AMI), commonly known as a heart attack, where the precise location of the heart muscle damage is not specified.AMI results from a sudden blockage in one or more coronary arteries, leading to a lack of oxygen supply to the heart muscle. This blockage is often caused by a build-up of plaque or a blood clot. The diagnosis is confirmed through laboratory tests detecting cardiac enzymes like troponin in the bloodstream, and/or electrocardiogram (ECG) findings.This code includes cases where the infarct is acute or has a duration of 4 weeks or less from onset.It excludes old myocardial infarctions (I25.2), post-myocardial infarction syndrome (I24.1), and subsequent type 1 myocardial infarctions (I22.-).
Example 1: A 65-year-old male presents to the emergency department with crushing chest pain radiating to his left arm. ECG shows ST-segment elevation. Troponin levels are elevated.He is diagnosed with an acute myocardial infarction, unspecified location., A 72-year-old female experiences sudden shortness of breath and nausea. She has no chest pain, but ECG and cardiac enzyme levels confirm an acute myocardial infarction. The specific location of the infarction cannot be definitively determined., A 58-year-old male with a history of hypertension and hyperlipidemia collapses at home. Paramedics find him unconscious. On arrival at the hospital, ECG shows non-specific ST-T changes and troponin is elevated. Following resuscitation, an acute myocardial infarction is diagnosed, but the exact location cannot be determined initially.
Detailed history of presenting symptoms (chest pain, shortness of breath, nausea, etc.), physical examination findings, electrocardiogram (ECG) results showing ST-segment elevation or depression, cardiac enzyme levels (troponin, CK-MB), and any other relevant diagnostic tests (e.g., echocardiogram).
** This code is often used in conjunction with other codes to fully describe the patient's condition and treatment.Always review the most up-to-date ICD-10-CM guidelines for accurate coding.
- Payment Status: Active
- Modifier TC rule: Not applicable to ICD-10 codes.
- Specialties:Cardiology, Emergency Medicine
- Place of Service:Emergency Room - Hospital, Inpatient Hospital