2026 ICD-10-CM Diagnosis Code I51.89Other ill-defined heart diseases

ICD-10-CM Codes›I00–I99›I30-I5A›I51

ICD-10-CM I51.89
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I51.89 is a billable ICD-10-CM diagnosis code for other ill-defined heart diseases. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 302 through 303. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other and ill-defined heart disease.

Code Identity

ICD-10-CM Code
I51.89
Billable Status
Yes — Valid for Submission
Code Describes
Other ill-defined heart diseases
Short Description
Other ill-defined heart diseases
Same as the full description in the CMS dataset.
Parent Code
I51.8
Other ill-defined heart diseases

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI30-I5AOther forms of heart disease
CategoryI51Complications and ill-defined descriptions of heart disease
This CodeI51.89Other ill-defined heart diseases

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormality of atrial septum
  • Abnormality of atrioventricular valve
  • Abnormality of left atrial appendage
  • Abnormality of right atrial appendage
  • Abnormality of tricuspid subvalvar apparatus
  • Abscess at site of systemic to pulmonary arterial shunt
  • Abscess of aorta
  • Abscess of aortic root
  • Abscess of aortic valve
  • Abscess of cardiac septum
  • Abscess of cardiovascular structure of trunk
  • Abscess of common atrioventricular valve
  • Abscess of heart
  • Abscess of left ventricular wall
  • Abscess of right ventricular wall
  • Abscess of truncal valve
  • Acquired abnormality of atrioventricular following repair of atrioventricular septal defect
  • Acquired abnormality of atrium
  • Acquired abnormality of cardiac ventricle
  • Acquired abnormality of left cardiac ventricle
  • Acquired abnormality of right atrium
  • Acquired abnormality of right cardiac ventricle
  • Acquired atrial septal defect
  • Acquired complete obstruction of aortic outflow
  • Acquired excessive restriction of interatrial communication
  • Acquired left ventricular outflow tract obstruction
  • Acquired narrowing of constructed cardiac intraventricular tunnel
  • Acquired right ventricular outflow tract obstruction
  • Acquired stenosis of subpulmonary area
  • Acquired subaortic stenosis
  • Acquired subpulmonary stenosis associated with functionally univentricular heart
  • Acquired subpulmonary stenosis due to restrictive ventricular defect associated with functionally univentricular heart
  • Acute/subacute carditis
  • Akinesis of apical anterior segment of left cardiac ventricle
  • Akinesis of apical inferior segment of left cardiac ventricle
  • Akinesis of apical lateral segment of left cardiac ventricle
  • Akinesis of apical septal segment of left cardiac ventricle
  • Akinesis of basal anterior segment of left cardiac ventricle
  • Akinesis of basal anterolateral segment of left cardiac ventricle
  • Akinesis of basal anteroseptal segment of left cardiac ventricle
  • Akinesis of basal inferior segment of left cardiac ventricle
  • Akinesis of basal inferolateral segment of left cardiac ventricle
  • Akinesis of basal inferoseptal segment of left cardiac ventricle
  • Akinesis of mid anterior segment of left cardiac ventricle
  • Akinesis of mid anterolateral segment of left cardiac ventricle
  • Akinesis of mid anteroseptal segment of left cardiac ventricle
  • Akinesis of mid inferior segment of left cardiac ventricle
  • Akinesis of mid inferolateral segment of left cardiac ventricle
  • Akinesis of mid inferoseptal segment of left cardiac ventricle
  • Akinesis of myocardium of anterior region of left ventricle
  • Akinesis of myocardium of anterolateral region of left ventricle
  • Akinesis of myocardium of anteroseptal region of left ventricle
  • Akinesis of myocardium of apex of left ventricle
  • Akinesis of myocardium of inferior region of left ventricle
  • Akinesis of myocardium of inferolateral region of left ventricle
  • Akinesis of myocardium of inferoseptal region of left ventricle
  • Akinesis of myocardium of lateral region of left ventricle
  • Akinesis of myocardium of septal region of left ventricle
  • Akinetic right ventricular wall
  • Annular abscess of aortic root
  • Anomalous bands of heart
  • Atrial cardiopathy
  • Atrial erosion caused by implanted device following atrial operation
  • Atrial thrombosis
  • Bacterial infectious disease of heart
  • Cardiac abnormality due to heart abscess
  • Cardiac dyskinesia
  • Cardiac polyp
  • Cardiac volume overload
  • Cardiotoxicity
  • Carditis
  • Chronic bacterial endocarditis
  • Chronic endocarditis
  • Dilatation of common atrioventricular valve annulus
  • Dilatation of left atrioventricular valve annulus
  • Dilatation of right atrioventricular valve annulus
  • Disorder of atrium following procedure
  • Disorder of cardiac function
  • Disorder of cardiac ventricle
  • Disorder of cardiac ventricle following procedure
  • Disorder of endocardium
  • Disorder of left atrium
  • Disorder of left atrium as complication of procedure
  • Disorder of left cardiac ventricle
  • Disorder of right atrium
  • Disorder of right atrium as complication of procedure
  • Dysfunction of left atrioventricular valve papillary muscle
  • Dysfunction of papillary muscle
  • Dysfunction of right atrioventricular valve papillary muscle
  • Dysfunction of right cardiac ventricle
  • Dysfunction of tricuspid valve papillary muscle
  • Erosion of left atrium due to and following implantation of device
  • Erosion of right atrium due to and following implantation of device
  • Excessive restriction of interatrial communication as complication of procedure
  • Foreign body in heart
  • Foreign body of cardiovascular structure
  • Functionally univentricular heart
  • Global hypokinesis of left cardiac ventricle
  • Hemodynamic instability
  • Hyperkinetic heart disease
  • Hyperkinetic right ventricular wall
  • Hyperkinetic ventricular wall
  • Hypokinesis of apical anterior segment of left cardiac ventricle
  • Hypokinesis of apical inferior segment of left cardiac ventricle
  • Hypokinesis of apical lateral segment of left cardiac ventricle
  • Hypokinesis of apical septal segment of left cardiac ventricle
  • Hypokinesis of basal anterior segment of left cardiac ventricle
  • Hypokinesis of basal anterolateral segment of left cardiac ventricle
  • Hypokinesis of basal anteroseptal segment of left cardiac ventricle
  • Hypokinesis of basal inferior segment of left cardiac ventricle
  • Hypokinesis of basal inferolateral segment of left cardiac ventricle
  • Hypokinesis of basal inferoseptal segment of left cardiac ventricle
  • Hypokinesis of mid anterior segment of left cardiac ventricle
  • Hypokinesis of mid anterolateral segment of left cardiac ventricle
  • Hypokinesis of mid anteroseptal segment of left cardiac ventricle
  • Hypokinesis of mid inferior segment of left cardiac ventricle
  • Hypokinesis of mid inferolateral segment of left cardiac ventricle
  • Hypokinesis of mid inferoseptal segment of left cardiac ventricle
  • Hypokinesis of myocardium of anterior region of left ventricle
  • Hypokinesis of myocardium of anterolateral region of left ventricle
  • Hypokinesis of myocardium of anteroseptal region of left ventricle
  • Hypokinesis of myocardium of apex of left ventricle
  • Hypokinesis of myocardium of inferior region of left ventricle
  • Hypokinesis of myocardium of inferolateral region of left ventricle
  • Hypokinesis of myocardium of inferoseptal region of left ventricle
  • Hypokinesis of myocardium of lateral region of left ventricle
  • Hypokinesis of myocardium of septal region of left ventricle
  • Hypokinesis of region of myocardium of left ventricle
  • Hypokinetic right ventricular wall
  • Incompetence of papillary muscle
  • Incoordination of papillary muscle
  • Infectious disease of heart
  • Interventricular cardiac septal hypertrophy
  • Interventricular dyssynchrony
  • Invasive aspergillosis
  • Invasive cardiac aspergillosis
  • Left heart obstructive lesion
  • Left ventricular abnormality
  • Left ventricular mass
  • Left ventricular systolic dysfunction
  • Left ventricular wall akinetic
  • Left ventricular wall dyskinetic
  • Left ventricular wall hypokinetic
  • Mild hypokinesis of cardiac wall
  • Mild left ventricular systolic dysfunction
  • Mild right ventricular systolic dysfunction
  • Mitral papillary muscle abnormality
  • Mitral papillary muscle dysfunction
  • Moderate hypokinesis of cardiac wall
  • Moderate left ventricular systolic dysfunction
  • Moderate right ventricular systolic dysfunction
  • Outflow tract abnormality in solitary indeterminate ventricle
  • Outflow tract obstruction in solitary indeterminate ventricle
  • Pancarditis
  • Papillary muscle atrophy
  • Papillary muscle degeneration
  • Papillary muscle disorder
  • Perforation of atrium following procedure
  • Perforation of left atrium due to and following procedure
  • Perforation of right atrium due to and following procedure
  • Postcapillary pulmonary hypertension
  • Postprocedural left ventricular outflow tract obstruction
  • Postprocedural right ventricular outflow tract obstruction
  • Pulmonary hypertension due to left heart disease
  • Restrictive interatrial communication
  • Right atrial abnormality
  • Right ventricle-dependent coronary circulation
  • Right ventricular abnormality
  • Right ventricular diastolic dysfunction
  • Right ventricular dysfunction due to disorder of left ventricle
  • Right ventricular function - finding
  • Right ventricular mass
  • Right ventricular outflow tract obstruction due to foreign body
  • Right ventricular systolic dysfunction
  • Right ventricular wall motion - finding
  • Scarring of papillary muscle
  • Severe hypokinesis of cardiac wall
  • Severe left ventricular systolic dysfunction
  • Severe right ventricular systolic dysfunction
  • Sinistrocardia
  • Structural disorder of heart
  • Subaortic outflow tract obstruction in solitary indeterminate ventricle
  • Subneopulmonary valve stenosis
  • Subpulmonary outflow tract obstruction in solitary indeterminate ventricle
  • Subpulmonary stenosis
  • Subpulmonary stenosis as complication of procedure
  • Subpulmonary stenosis associated with functionally univentricular heart as complication of procedure
  • Thickened atrial septum
  • Thin ventricular septum
  • Thrombus of right atrium
  • Tricuspid papillary muscle abnormality
  • Variant dominance of coronary circulation
  • Ventricular asynergy

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Carditis (acute)(chronic)
  • Pancarditis (acute)(chronic)

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Asynergia, asynergy
      • ventricular
    • Carditis(acute) (bacterial) (chronic) (subacute)
    • Disease, diseased
      • heart (organic)
        • functional
    • Disorder(of)
      • cardiac, functional
    • Displacement, displaced
      • heart (congenital)
        • acquired
    • Dysfunction
      • heart
    • Dysfunction
      • papillary muscle
    • Hemorrhage, hemorrhagic(concealed)
      • heart
    • Hyperkinesia, hyperkinetic(disease) (reaction) (syndrome) (childhood) (adolescence)
      • heart
    • Incompetency, incompetent, incompetence
      • chronotropic
        • with
          • left ventricular dysfunction
    • Pancarditis(acute) (chronic)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR CIR015
Other and ill-defined heart disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Cardiotoxicity

    damage to the heart or its function secondary to exposure to toxic substances such as drugs used in chemotherapy; immunotherapy; or radiation.

  • Acute Purulent Pericarditis|Acute purulent pericarditis

    a rare, life-threatening bacterial or fungal infection that is characterized by a severe and sudden onset and an accumulation of pus in the pericardial sac.

  • Grade 1 Myocarditis, CTCAE 6.0

    asymptomatic with lab or ecg findings only

  • Grade 2 Myocarditis, CTCAE 6.0

    symptoms with moderate activity or exertion

  • Grade 3 Myocarditis, CTCAE 6.0

    severe with symptoms at rest or with minimal activity or exertion; intervention indicated; new onset of symptoms

  • Grade 4 Myocarditis, CTCAE 6.0

    life-threatening consequences; urgent intervention indicated (e.g., continuous iv therapy or mechanical hemodynamic support); hemodynamically unstable requiring non-invasive or invasive ventilation; complete or high grade av block; significant ventricular arrhythmia

  • Grade 5 Myocarditis, CTCAE 6.0

    death

  • Myocarditis, CTCAE 6.0

    a disorder characterized by inflammation of the muscle tissue of the heart.

  • Myocarditis, CTCAE|Myocarditis|Myocarditis|Myocarditis, CTCAE 5.0

    a disorder characterized by inflammation of the muscle tissue of the heart.

  • Acute and Subacute Endocarditis, Unspecified|Acute and subacute endocarditis, unspecified

    evidence of acute and subacute endocarditis.

  • Acute and Subacute Infective Endocarditis|Acute and subacute infective endocarditis

    evidence of acute and subacute infective endocarditis.

  • Acute Endocarditis

    acute inflammation of the endocardium. bacteria is the usual etiologic agent, and the distinction between "acute" and "subacute" has traditionally been made based on the pathogenic organism and clinical presentation.

  • Acute Myocardial Injury with Myocarditis Related to COVID-19|Acute myocardial injury with myocarditis

    acute myocardial injury with clinical, imaging, and or pathology evidence supporting myocarditis in a patient with probable or confirmed acute covid-19.

  • Acute Myocardial Injury without Ischemia, Heart Failure, Ventricular Dysfunction, or Myocarditis Related to COVID-19|Acute myocardial injury without ischemia, HF, ventricular dysfunction, or myocarditis

    acute myocardial injury, without evidence of acute ischemia, heart failure, a newly reduced left or right ventricular ejection fraction, cardiogenic shock, or myocarditis in a patient with probable or confirmed acute covid-19.

  • Acute Myocarditis

    the sudden onset of inflammation of heart muscle with myocellular necrosis; this is generally secondary to an infectious cause, and patients often have a recent history of a flu-like illness.

  • Acute Pericarditis

    acute inflammation of the pericardium.

  • Acute Pericarditis Related to COVID-19|Acute pericarditis

    acute pericarditis in a patient with probable or confirmed acute covid-19.

  • Acute Rheumatic Endocarditis|Acute rheumatic endocarditis|Rheumatic diseases of endocardium, valve unspecified

    inflammation of the endocardium in acute rheumatic heart disease.

  • Acute Rheumatic Myocarditis

    inflammation of the myocardium in acute rheumatic heart disease.

  • Acute Rheumatic Pericarditis

    inflammation of the pericardium in acute rheumatic heart disease.

  • Bacterial Endocarditis

    endocarditis that is caused by an infection with a bacterial agent.

  • Bacterial Myocarditis

    myocarditis that is caused by an infection with a bacterial agent.

  • Bacterial Pericarditis

    pericarditis that is caused by an infection with a bacterial agent.

  • Candidal Endocarditis|Candidal endocarditis

    endocarditis caused by fungal infection with candida species.

  • Carditis

    inflammation of the heart or its surroundings. (acc/aha)

  • Constrictive Pericarditis|Constrictive pericarditis

    a heart disorder in which the pericardial sac becomes thickened and fibrotic, tightening the myocardium and impeding the normal myocardial function.

  • Early Prosthetic Valve Endocarditis

    prosthetic valve endocarditis that occurs days to weeks after surgery.

  • Endocarditis and Heart Valve Disorder in Disease Classified Elsewhere|Endocarditis and heart valve disorder in disease classified elsewhere

    evidence of endocarditis and heart valve disorder in disease classified elsewhere.

  • Endocarditis in Systemic Lupus Erythematosus|Endocarditis in systemic lupus erythematosus

    evidence of endocarditis in systemic lupus erythematosus.

  • Endocarditis Infective, CTCAE|Endocarditis Infective|Endocarditis infective

    a disorder characterized by an infectious process involving the endocardial layer of the heart.

  • Endocarditis, Valve Unspecified|Endocarditis, valve unspecified

    evidence of endocarditis, valve unspecified.

  • Endocarditis|endocarditis

    inflammation of the endocardium.

  • Fungal Pericarditis

    pericarditis that is caused by an infection with a fungal agent.

  • Giant Cell Myocarditis

    an often fatal inflammatory disorder that affects the myocardium. morphologically, it is characterized by the presence of an inflammatory infiltrate in the myocardial tissue that includes multinucleated giant cells. it is often associated with the presence of an autoimmune disorder. patients present with arrhythmias and/or heart failure. heart transplantation is the only treatment option available.

  • Grade 1 Pericarditis, CTCAE|Grade 1 Pericarditis|Grade 1 Pericarditis

    asymptomatic, ecg or physical findings (e.g., rub) consistent with pericarditis

  • Grade 2 Myocarditis, CTCAE|Grade 2 Myocarditis

    symptoms with moderate activity or exertion

  • Grade 2 Pericarditis, CTCAE|Grade 2 Pericarditis|Grade 2 Pericarditis

    symptomatic pericarditis (e.g., chest pain)

  • Grade 3 Endocarditis Infective, CTCAE|Grade 3 Endocarditis infective

    iv antibiotic, antifungal, or antiviral intervention indicated; invasive intervention indicated

  • Grade 3 Myocarditis, CTCAE|Grade 3 Myocarditis|Grade 3 Myocarditis

    severe with symptoms at rest or with minimal activity or exertion; intervention indicated; new onset of symptoms

  • Grade 3 Pericarditis, CTCAE|Grade 3 Pericarditis|Grade 3 Pericarditis

    pericarditis with physiologic consequences (e.g., pericardial constriction)

  • Grade 4 Endocarditis Infective, CTCAE|Grade 4 Endocarditis infective

    life-threatening consequences; urgent intervention indicated

  • Grade 4 Myocarditis, CTCAE|Grade 4 Myocarditis|Grade 4 Myocarditis

    life-threatening consequences; urgent intervention indicated (e.g., continuous iv therapy or mechanical hemodynamic support)

  • Grade 4 Pericarditis, CTCAE|Grade 4 Pericarditis|Grade 4 Pericarditis

    life-threatening consequences; urgent intervention indicated

  • Grade 5 Endocarditis Infective, CTCAE|Grade 5 Endocarditis infective

    death

  • Grade 5 Myocarditis, CTCAE|Grade 5 Myocarditis|Grade 5 Myocarditis

    death

  • Grade 5 Pericarditis, CTCAE|Grade 5 Pericarditis|Grade 5 Pericarditis

    death

  • Immune Checkpoint Inhibitor-related Myocarditis|ICI-MC

    myocarditis associated with the therapeutic use of an immune checkpoint inhibitor.

  • Infective Endocarditis Prophylaxis

    the use of antibiotics for the prevention of endocarditis.

  • Infective Endocarditis|Endocarditis infective

    an infectious process involving the endocardial layer of the heart.

  • Interstitial Myocarditis

    inflammation of the heart characterized by infiltration of the interstitial tissues by inflammatory cells, histiocytes, and the formation of granulomas. giant cells are often present.

  • Late Prosthetic Valve Endocarditis

    prosthetic valve endocarditis that occurs several months to years following valve replacement.

  • Listerial Endocarditis|Listerial endocarditis

    endocarditis caused by bacterial infection with listeria species.

  • Malignant Pericarditis|Pericarditis, Malignant

    pericarditis caused by the infiltration of the pericardium by a malignant neoplasm. the diagnosis is based on the cytological examination of pericardial fluid or the histologic examination of pericardial tissue.

  • Meningococcal Endocarditis|Meningococcal endocarditis

    endocarditis caused by bacterial infection with meningococcus species.

  • Myocarditis

    inflammation of the muscle tissue of the heart.

  • Myocarditis, CTCAE 5.0|Myocarditis|Myocarditis

    a disorder characterized by inflammation of the muscle tissue of the heart.

  • Native Valve Endocarditis

    endocarditis affecting a native valve of the heart.

  • Pericarditis

    an inflammatory process affecting the pericardium.

  • Pericarditis Associated with Post-Acute Sequelae of SARS-CoV-2 Infection|PASC Pericarditis|PASC pericarditis|Post-Acute Sequelae of COVID-19 Pericarditis

    pericarditis that started during probable or confirmed acute covid-19 and persisted beyond four weeks after the initial diagnosis of covid-19.

  • Pericarditis in Systemic Lupus Erythematosus|Pericarditis in systemic lupus erythematosus

    evidence of pericarditis in systemic lupus erythematosus.

  • Pericarditis, CTCAE|Pericarditis|Pericarditis|Pericarditis

    a disorder characterized by irritation to the layers of the pericardium (the protective sac around the heart).

  • Prosthetic Valve Endocarditis

    endocarditis occurring on parts of a valve prosthesis or a reconstructed heart valve; it can be classified into early and late prosthetic valve endocarditis.

  • ST Elevation Pericarditis by ECG Finding|ST ELEVATION PERICARDITIS|ST Elevation Pericarditis|ST Elevation Pericarditis by EKG Finding|ST elevation pericarditis

    an electrocardiographic finding of st elevation which is concave upwards, and which is often accompanied by pr segment depression. (cdisc)

  • Subacute Bacterial Endocarditis|SBE

    subacute inflammation of the endocardium. streptococcus viridans is the usual etiologic agent of subacute bacterial endocarditis. the distinction between "acute" and "subacute" endocarditis has traditionally been made based on the pathogenic organism and clinical presentation.

  • Syphilitic Endocarditis|Syphilitic endocarditis

    endocarditis secondary to syphilis.

  • Uremic Pericarditis

    inflammation of the pericardium associated with chronic kidney failure.

  • Viral Endocarditis|Viral endocarditis

    endocarditis caused by a viral infection.

  • Viral Myocarditis|Myocarditis

    myocarditis that is caused by an infection with a viral agent.

  • Viral Pericarditis

    pericarditis that is caused by an infection with a viral agent.

Patient EducationClinical

Heart Diseases

Heart disease is a general term that includes many types of heart problems. It's a type of cardiovascular disease, which means heart and blood vessel disease.

The full article covers:

  • What is heart disease?
  • What are the types of heart disease?
  • What causes heart diseases?
  • Who is more likely to develop heart diseases?
  • What are the symptoms of heart disease?
  • How are heart diseases diagnosed?
  • What are the treatments for heart disease?
  • Can heart diseases be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert I51.89 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
429.81 Papillary muscle dis NEC
Approximate The match is approximate rather than exact.
ICD-9-CM
429.82 Hyperkinetic heart dis
Approximate The match is approximate rather than exact.
ICD-9-CM
429.89 Ill-defined hrt dis NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About I51.89Overview

Is I51.89 (Other ill-defined heart diseases) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other ill-defined heart diseases on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I51.89 group to?

When other ill-defined heart diseases is the principal diagnosis on an inpatient stay, it groups to MS-DRG 302, 303, with relative weights from 0.6732 to 1.1966 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of I51.89?

Under the General Equivalence Mappings, other ill-defined heart diseases converts to ICD-9-CM 429.81 (papillary muscle dis NEC), 429.82 (hyperkinetic heart dis), and 429.89 (ill-defined hrt dis NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.