How To Code Some Common Cardiac Conditions

by | Published on Oct 4, 2021 | Specialty Coding

Cardiac Conditions
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Cardiac conditions refer to cardiovascular or heart diseases that affect the structures or function of heart. According to the WHO, cardiovascular diseases (CVDs) are the leading cause of death globally, taking an estimated 17.9 million lives each year, and more than four out of five CVD deaths are due to heart attacks and strokes. Proper documentation and coding is essential to streamline the cardiology billing process. Cardiologists and other specialists treating such conditions can choose a professional medical coding company to report the diagnosis and treatments accurately on their medical claims.

Here are some common cardiac conditions and the ICD-10 codes to report them.

Coronary Artery Disease

Coronary artery disease (CAD) occurs when the heart’s blood vessels – the coronary arteries – become narrowed or blocked and fail to supply enough blood to the heart. The condition can lead to angina or a heart attack. For patients with angina in the setting of CAD, coders will choose a combination code in ICD-10-CM that identifies CAD and the presence of angina pectoris as well as its type, if specified.

To report CAD in a transplanted heart, coders can use I25.75- for CAD of the native artery and I25.76- for CAD of a bypass graft.

For patients without angina pectoris, coders can use I25.10.

  • I25 Chronic ischemic heart disease
    • I25.1 Atherosclerotic heart disease of native coronary artery
      • I25.10 …… without angina pectoris
      • I25.11 Atherosclerotic heart disease of native coronary artery with angina pectoris
      • I25.110 Atherosclerotic heart disease of native coronary artery with unstable angina pectoris
      • I25.111 …… with documented spasm
      • I25.118 Atherosclerotic heart disease of native coronary artery with other forms of angina pectoris
      • I25.119 Atherosclerotic heart disease of native coronary artery with unspecified angina pectoris

Heart Attack

Heart attack or myocardial infarction (MI) occurs when one or more coronary arteries that supply blood to the heart muscles become completely blocked. This blockage of a coronary artery deprives the heart muscle of blood and oxygen, causing injury to the heart muscle. During documentation, myocardial infarction is classified as ST elevation myocardial infarctions (STEMI) or non-ST elevation myocardial infarctions (NSTEMI).

It is also important to document the location of the infarction (Anterior wall, Inferior wall or Other), onset of MI (8 weeks or less, 4 weeks or less) and episode of care (Initial or Subsequent episode of care, Event or Initial and/or Subsequent).

  • I21 Acute myocardial infarction
    • I21.0 ST elevation (STEMI) myocardial infarction of anterior wall
    • I21.1 ST elevation (STEMI) myocardial infarction of inferior wall
    • I21.2 ST elevation (STEMI) myocardial infarction of other sites
    • I21.3 ST elevation (STEMI) myocardial infarction of unspecified site
    • I21.4 Non-ST elevation (NSTEMI) myocardial infarction
    • I21.9 Acute myocardial infarction, unspecified
    • I21.A Other type of myocardial infarction
      • I21.A1 Myocardial infarction type 2
      • I21.A9 Other myocardial infarction type
  • I25.2 Old myocardial infarction


Coders should also be able to distinguish cerebral and precerebral arteries because ICD-10-CM codes make this distinction. The codes I60-I62 specify the location or source of a hemorrhage as well as its laterality.

  • I60 Nontraumatic subarachnoid hemorrhage
    • I60.0 Nontraumatic subarachnoid hemorrhage from carotid siphon and bifurcation
    • I60.1 Nontraumatic subarachnoid hemorrhage from middle cerebral artery
  • I61 Nontraumatic intracerebral hemorrhage
    • I61.0 Nontraumatic intracerebral hemorrhage in hemisphere, subcortical
    • I61.1 Nontraumatic intracerebral hemorrhage in hemisphere, cortical
  • I62 Other and unspecified nontraumatic intracranial hemorrhage
    • I62.0 Nontraumatic subdural hemorrhage
    • I62.1 Nontraumatic extradural hemorrhage

Code I63 specifies the cause of the ischemic stroke such as thrombosis or unspecified, specific location and laterality of the occlusion.

  • I63 Cerebral infarction
    • I63.0 Cerebral infarction due to thrombosis of precerebral arteries
    • I63.1 Cerebral infarction due to embolism of precerebral arteries
  • I63.4 Cerebral infarction due to embolism of cerebral arteries
    • I63.40 Cerebral infarction due to embolism of unspecified cerebral artery
    • I63.41 Cerebral infarction due to embolism of middle cerebral artery
  • I63.5 Cerebral infarction due to unspecified occlusion or stenosis of cerebral arteries
    • I63.50 Cerebral infarction due to unspecified occlusion or stenosis of unspecified cerebral artery
    • I63.51 Cerebral infarction due to unspecified occlusion or stenosis of middle cerebral artery
  • I63.6 Cerebral infarction due to cerebral venous thrombosis, nonpyogenic
  • I63.8 Other cerebral infarction
    • I63.81 …… due to occlusion or stenosis of small artery
    • I63.89 Other cerebral infarction
  • I63.9 Cerebral infarction, unspecified

For a patient with a history of cerebrovascular disease without any neurologic deficits, use the code Z86.73 and a code for the cerebral infarction without residual deficits (not code I69).

  • Z86.73 Personal history of transient ischemic attack (TIA), and cerebral infarction without residual deficits


Cardiomyopathy is a condition that causes the heart muscle to become enlarged, thick, or rigid. As this disorder progresses, the heart becomes weaker and can lead to heart failure, blood clots or irregular heartbeats called arrhythmias. ICD-10-CM has unique codes for the different types of cardiomyopathy.

  • I42 – Cardiomyopathy
    • I42.0 – Dilated cardiomyopathy
    • I42.1 – Obstructive hypertrophic cardiomyopathy
    • I42.2 – Other hypertrophic cardiomyopathy
    • I42.3 – Endomyocardial (eosinophilic) disease
    • I42.4 – Endocardial fibroelastosis
    • I42.5 – Other restrictive cardiomyopathy
    • I42.6 – Alcoholic cardiomyopathy
    • I42.7 – Cardiomyopathy due to drug and external agent
    • I42.8 – Other cardiomyopathies
    • I42.9 – Cardiomyopathy, unspecified
  • I43 – Cardiomyopathy in diseases classified elsewhere

Atrial Fibrillation:

Atrial fibrillation refers to irregular heartbeat or arrhythmia that can cause a patient to develop blood clots, stroke, heart failure or other conditions. When reporting multiple types of atrial fibrillation in the record, select the most specific type.

  • I48 Atrial fibrillation and flutter
    • I48.0 Paroxysmal atrial fibrillation
    • I48.1 Persistent atrial fibrillation
      • I48.11 Longstanding persistent atrial fibrillation
      • I48.19 Other persistent atrial fibrillation
    • I48.2 Chronic atrial fibrillation
      • I48.20 …… unspecified
      • I48.21 Permanent atrial fibrillation
    • I48.9 Unspecified atrial fibrillation and atrial flutter
      • I48.91 Unspecified atrial fibrillation

Clear documentation is important for accurate and proper medical coding. To report conditions using correct diagnosis and procedure codes and to submit error-free medical claims, practices can rely on experienced cardiology medical billing service providers. Make sure that the coders are familiar with changing coding and billing standards.

Natalie Tornese

Holding a CPC certification from the American Academy of Professional Coders (AAPC), Natalie is a seasoned professional actively managing medical billing, medical coding, verification, and authorization services at OSI.

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