Coding Tip: Cardiomyopathy

June 1, 2023
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Coding Tips of the Month: Cardiomyopathy

OHN provides the knowledge, resources, processes, and technology you need for success in value-based care so you can do more of what you love –taking care of patients. Each month, we share one coding tip and highlight one best practice advisory (BPA) to help to support your clinical documentation efforts.

Additionally, the clinical documentation excellence (CDE) team is here to support you – email with any questions.

Capturing and Coding Cardiomyopathy


  • Cardiomyopathy is a disease of the heart muscle that impairs the function of the heart.
  • Cardiomyopathy can be classified as primary or secondary and ischemic or nonischemic.
  • Primary cardiomyopathy is a noninflammatory disease of the heart muscle, often of obscure or unknown cause, which occurs in the absence of other cardiac conditions or systemic disease processes.
  • Secondary cardiomyopathy is caused by a known medical condition, such as hypertension, valve disease, congenital heart disease or coronary artery disease.
  • Ischemic cardiomyopathy is caused by coronary artery disease and heart attacks, which result in lack of blood flow to the heart muscle that leads to damage of the heart muscle.
  • Nonischemic cardiomyopathy is a type of cardiomyopathy that is not related to coronary artery disease or poor coronary artery blood flow. The three main types of nonischemic cardiomyopathy are:
  • Dilated cardiomyopathy (also known as congestive cardiomyopathy) – the most common type of cardiomyopathy in which the heart’s main pumping chamber, the left ventricle, becomes enlarged(dilated), and its pumping ability becomes less forceful, so blood doesn’t flow as easily through the heart
  • Hypertrophic cardiomyopathy –abnormal growth or thickening of the heart muscle, particularly affecting the muscle of the left ventricle, which often causes the heart to stiffen and the pumping chamber to shrink in size, interfering with the heart’s ability to deliver blood to the body
  • § Restrictive cardiomyopathy – the heart muscle becomes rigid and less elastic, meaning the heart can’t properly expand and fill with blood between heartbeats

How To Code & Document


  • In the subjective section of the office note, document current related patient complaints and symptoms. If there are none, this note should show that the patient was screened for current related complaints or symptoms.


  • Include any current associated physical exam findings – such as edema/swelling of the lower extremities, abdomen or neck veins – and related diagnostic testing results.


  • Specificity: The term “cardiomyopathy” is broad and nonspecific. It is important to describe the particular type of cardiomyopathy to the highest level of specificity.


  • Limit, or avoid altogether, the use of abbreviations. There are several commonly used medical abbreviations for different types of cardiomyopathy (e.g., CM, CMP,HCM, HOCM), but some of these abbreviations have other meanings.
  • Document the specific type of cardiomyopathy by spelling it out in full.

Current vs Historical/Transient

  • Do not use the descriptor “history of” to describe current cardiomyopathy. In diagnosis coding, “history of” means the condition occurred in the past and is no longer a current problem.
  • Temporary or transient cardiomyopathy that occurred in the past and is no longer present should not be documented as if it is current.

Treatment Plan

  • Document a specific and concise treatment plan.
  • Clearly link the cardiomyopathy diagnosis to any medications being used to treat the condition.
  • Document referrals to specialists or other providers.
  • Include the date of the patient’s next appointment.

Treatment Options

Lifestyle changes:

  • Heart-healthy diet
  • Weight control
  • Stress management
  • Physical activity and exercise
  • Smoking cessation


  • Blood thinners to prevent clots
  • Antiarrhythmics to control heart rate and rhythm
  • Antihypertensives for blood pressure control
  • Diuretics (“water pills”) to remove excess sodium and reduce excess fluid in the blood

Nonsurgical procedures:

  • Alcohol septal ablation, in which a type of alcohol (ethanol) is injected through a tube into the small artery that supplies blood to the thickened area of heart muscle. The alcohol shrinks the thickened heart tissue to a more normal size, allowing blood to flow freely through the ventricle of the heart, which results in improved symptoms.
  • Cardiac device implantation: Pacemaker, Cardioverter-defibrillator, Left ventricular assist device

Surgical procedures:

  • Heart transplant – a last resort for severe, end-stage cardiomyopathy that cannot be controlled by other means

Coding Cardiomyopathy

Many of the most common cardiomyopathies classify to category I42, Cardiomyopathy. A fourth character is required to specify the particular type of cardiomyopathy.

  • The broad and nonspecific final diagnosis of “cardiomyopathy” leads to the broad and nonspecific diagnosis code I42.9, Cardiomyopathy, unspecified.
  • Code I42.9 should be assigned only when no information in the medical record identifies the particular type of cardiomyopathy.

Hypertensive cardiomyopathy classifies to categoryI11, Hypertensive heart disease, with an additional code of I43, Cardiomyopathy in diseases classified elsewhere.

Congestive cardiomyopathy is also known as dilated cardiomyopathy. Both of these descriptions classify to code I42.Ø, Dilated cardiomyopathy.

  • Congestive cardiomyopathy often is associated with congestive heart failure and has basically the same symptoms.
  • Treatment typically focuses on management of the congestive heart failure; therefore, heart failure (category I5Ø) is reported as the principal diagnosis with an additional code for the cardiomyopathy.

Hypertrophic cardiomyopathy can be obstructive or nonobstructive.

  • I42.1 Obstructive hypertrophic cardiomyopathy
  • I42.2 Other hypertrophic cardiomyopathy
  • Includes nonobstructive hypertrophic cardiomyopathy

Takotsubo cardiomyopathy is a reversible form of cardiomyopathy that classifies to code I51.81, Takotsubo syndrome. This code includes the following conditions:

  • Reversibleleft ventricular dysfunction following sudden emotional stress
  • Stress-induced cardiomyopathy
  • Takotsubo cardiomyopathy
  • Transient left ventricular apical ballooning syndrome

Dilated cardiomyopathy and ischemic cardiomyopathy are classified to different codes. When a medical record documents a current diagnosis of ischemic dilated cardiomyopathy, both codes are needed to fully capture this condition:

  • I25.5 Ischemic cardiomyopathy
  • I42.Ø Dilated cardiomyopathy

Nonischemic cardiomyopathy with no other description and no mention of cause codes to I42.8.

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