2026 ICD-10-CM Diagnosis Code I50.9Heart failure, unspecified

ICD-10-CM Codes›I00–I99›I30-I5A›I50

ICD-10-CM I50.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I50.9 is a billable ICD-10-CM diagnosis code for heart failure, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 291 through 293, 791, 793. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Heart failure.

For Medicare Advantage risk adjustment, I50.9 maps to CMS-HCC Category 226 (Heart Failure, Except End Stage and Acute) under the V28 model, adding a risk factor of about 0.360 for a community, non-dual, aged beneficiary in payment year 2026.

This medical diagnosis code is frequently used in Cardiology medical specialties to designate conditions such heart failure.

Code Identity

ICD-10-CM Code
I50.9
Billable Status
Yes — Valid for Submission
Code Describes
Heart failure, unspecified
Short Description
Heart failure, unspecified
Same as the full description in the CMS dataset.
Parent Code
I50
Heart failure

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI30-I5AOther forms of heart disease
CategoryI50Heart failure
This CodeI50.9Heart failure, unspecified

Medicare Risk Adjustment (HCC)Billing

I50.9 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2026.

CMS-HCC V28 Category (Payment Model)
HCC 226— Heart Failure, Except End Stage and Acute
Payment HCC · PY 2026 one of 34 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+0.360
community, non-dual, aged · ranges 0.217–0.537 across segments
Hierarchy
Superseded by HCC 221, HCC 222, HCC 223, HCC 224, and HCC 225
a more severe related category takes the payment when both are reported
Prior Model (CMS-HCC V24)
HCC 85
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 85 · ESRD (V21): HCC 85 · ESRD (V24): HCC 85
ESRD V21 weights: 0.082 dialysis, 0.186–0.336 functioning graft · ESRD V24 weights: 0.063 dialysis, 0.169–0.302 functioning graft
Part D (RxHCC)
RxHCC 186 — Heart Failure
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2026 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute congestive heart failure
  • Acute exacerbation of chronic congestive heart failure
  • Acute exacerbation of chronic heart failure
  • Acute heart failure
  • Acute heart failure co-occurrent with normal ejection fraction
  • Acute on chronic heart failure co-occurrent with normal ejection fraction
  • Benign hypertensive heart disease
  • Benign hypertensive heart disease with congestive cardiac failure
  • Cardiac arrest AND/OR failure following anesthesia AND/OR sedation in labor AND/OR delivery
  • Cardiac arrest due to procedure
  • Cardiac arrest during procedure
  • Cardiac arrest following obstetric procedure
  • Cardiac arrhythmia during pregnancy
  • Cardiac edema
  • Cardiac insufficiency during AND/OR resulting from a procedure
  • Cardiac insufficiency following cardiac surgery
  • Cardiorenal syndrome
  • Chronic congestive heart failure
  • Chronic heart failure
  • Chronic heart failure co-occurrent with normal ejection fraction
  • Compensated cardiac failure
  • Complication due to cardiac conduit operation
  • Congestive heart failure
  • Congestive heart failure as early postoperative complication
  • Congestive heart failure as post-operative complication of cardiac surgery
  • Congestive heart failure as post-operative complication of non-cardiac surgery
  • Congestive heart failure due to cardiomyopathy
  • Congestive heart failure due to valvular disease
  • Congestive heart failure stage B
  • Congestive heart failure stage B due to ischemic cardiomyopathy
  • Congestive heart failure stage C
  • Congestive heart failure stage C due to ischemic cardiomyopathy
  • Congestive heart failure stage D
  • Congestive rheumatic heart failure
  • Decompensated cardiac failure
  • Decompensated chronic heart failure
  • Diastolic dysfunction
  • Disorder confirmed
  • Exacerbation of congestive heart failure
  • Heart disease due to thyrotoxicosis
  • Heart failure
  • Heart failure confirmed
  • Heart failure due to end stage congenital heart disease
  • Heart failure due to thyrotoxicosis
  • Heart failure following administration of antineoplastic agent
  • Heart failure following obstetric procedure
  • Heart failure with normal ejection fraction
  • Heart failure with reduced ejection fraction
  • Heart failure with reduced ejection fraction due to cardiomyopathy
  • Heart failure with reduced ejection fraction due to coronary artery disease
  • Heart failure with reduced ejection fraction due to heart valve disease
  • Heart failure with reduced ejection fraction due to myocarditis
  • Hypertensive heart AND chronic kidney disease with congestive heart failure
  • Hypertensive heart and renal disease with heart failure
  • Hypertensive heart and renal disease with both heart failure and renal failure
  • Hypertensive heart disease with congestive heart failure
  • Hypertensive heart failure
  • Hypertensive renal failure
  • Low cardiac output syndrome
  • Low output heart failure
  • Low output heart failure due to and following Fontan operation
  • Malignant hypertensive heart disease
  • Malignant hypertensive heart disease with congestive heart failure
  • Nail changes associated with systemic disease
  • Normal cardiac ejection fraction
  • Normal cardiac function
  • Obstetrical cardiac complication of anesthesia AND/OR sedation
  • Obstetrical complication of anesthesia AND/OR sedation
  • Pleural effusion due to another disorder
  • Pleural effusion due to congestive heart failure
  • Red half-moon nail in congestive heart failure
  • Refractory heart failure
  • Symptomatic congestive heart failure
  • X-linked intellectual disability, cardiomegaly, congestive heart failure syndrome

Tabular List NotesGuidance

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

Inclusion Terms

  • Cardiac, heart or myocardial failure NOS
  • Congestive heart disease
  • Congestive heart failure NOS

Type 2 Excludes

  • fluid overload unrelated to congestive heart failure E87.70

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

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

CCSR CIR019
Heart failure
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Heart Failure

    a heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction.

  • Heart Failure, Diastolic

    heart failure caused by abnormal myocardial relaxation during diastole leading to defective cardiac filling.

  • Heart Failure, Systolic

    heart failure caused by abnormal myocardial contraction during systole leading to defective cardiac emptying.

  • Diastole

    post-systolic relaxation of the heart, especially the heart ventricles.

  • Systole

    period of contraction of the heart, especially of the heart ventricles.

  • Diastolic Dysfunction

    impairment in the filling of the ventricles during diastole. causes include hypertrophic and restrictive cardiomyopathies, coronary artery disease, chronic high blood pressure, aortic stenosis, and aging.

  • Left Ventricular Diastolic Dysfunction, CTCAE|Left ventricular diastolic dysfunction

    an adverse event characterized by impaired functioning of the left ventricle of the heart during the diastole phase of the cardiac cycle.

  • Cardiorenal Syndrome

    a disorder of the heart and kidneys in which dysfunction of one of the organs induces dysfunction of the other organ.

Patient EducationClinical

Heart Failure

Heart failure means that your heart can't pump enough oxygen-rich blood to meet your body's needs. Heart failure doesn't mean that your heart has stopped or is about to stop beating. But without enough blood flow, your organs may not work well, which can cause serious problems.

The full article covers:

  • What is heart failure?
  • What causes heart failure?
  • Who is more likely to develop heart failure?
  • What are the symptoms of heart failure?
  • What other problems does heart failure cause?
  • How is heart failure diagnosed?
  • What are the treatments for heart failure?
  • Can heart failure be prevented?

Read the full article at MedlinePlus

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

Convert I50.9 to ICD-9-CMHistory

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

ICD-9-CM
428.0 CHF NOS
Approximate The match is approximate rather than exact.
ICD-9-CM
428.9 Heart failure NOS
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 I50.9Overview

What is the ICD-10 code for heart failure, unspecified?

The ICD-10-CM code for heart failure, unspecified is I50.9 (sometimes written as I509). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is I50.9 (Heart failure) a billable code?

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

What MS-DRG does I50.9 group to?

When heart failure, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 291, 292, 293, 791, 793, with relative weights from 0.5660 to 4.1696 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of I50.9?

Under the General Equivalence Mappings, heart failure, unspecified converts to ICD-9-CM 428.0 (CHF NOS) and 428.9 (heart failure NOS). The mapping is approximate, so confirm the match fits the documentation.

What HCC is I50.9?

I50.9 (heart failure, unspecified) maps to CMS-HCC Category 226 (Heart Failure, Except End Stage and Acute), commonly written as HCC 226, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 85 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 186.

Does I50.9 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, I50.9 adds a risk adjustment factor of about 0.360 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.217 to 0.537 depending on the payment segment). A more severe related category (HCC 221, HCC 222, HCC 223, HCC 224, and HCC 225) supersedes it when both are reported. See the full factor table on the HCC 226 category page.