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I50.9ICD-10-CM

Heart failure, unspecified

BillableMaps to an HCCSix code-first conditionsNo code exists for CHF as such

How the code is built

I

Chapter

Diseases of the circulatory system

50

Category

Heart failure

9

Char 4

Neither type nor acuity specified

Chapter

I00 to I99

Diseases of the circulatory system

Block

I30 to I5A

Other forms of heart disease

Category

I50

Heart failure, not billable on its own

Billable

Yes

Complete at 4 characters

Code first at I50

Six conditions, including hypertensive heart disease

The hypertensive code leads

Excludes2 at I50

Cardiac arrest, neonatal cardiac failure

Permissions, not prohibitions

Risk adjustment

HCC mapped

The heart failure category excluding end-stage and acute, under CMS-HCC V28

DefinitionCode structureClinical pictureDocumentationDecision guideTabular listComparisonClaim contextRisk adjustmentDenialsSources

Key takeaways

  • I50.9 codes heart failure when neither the type nor the acuity is documented
  • ICD-10-CM has no code for congestive heart failure as such, so CHF lands here by default
  • When hypertension is present, the hypertensive heart disease code is sequenced first, and an I50 code is still required
  • Cardiac arrest and neonatal cardiac failure are Excludes2, so neither is prohibited alongside
  • It is billable, and it maps to an HCC, but the model now pays end-stage and acute heart failure through separate categories
1Definition

What ICD-10 code I50.9 means

I50.9 is the ICD-10-CM code for heart failure, unspecified. It applies when a provider documents heart failure without identifying whether it is systolic, diastolic, or combined, and without stating whether it is acute, chronic, or acute on chronic.

There is no code for congestive heart failure. ICD-9-CM had one, and ICD-10-CM deliberately did not carry it forward. The term CHF describes a clinical picture rather than a classification entity, so it lands at I50.9 along with heart failure NOS, cardiac failure, and myocardial failure. That is why this code is among the highest-volume cardiovascular diagnoses reported and among the most frequently left unspecified when the chart supports a more specific code.

Code

I50.9

Descriptor

Heart failure, unspecified

Chapter

Diseases of the circulatory system

Block

Other forms of heart disease

Category

I50, heart failure

Billable

Yes

Code first at I50

Hypertensive heart disease, hypertension with chronic kidney disease, post-surgical, rheumatic, and two obstetric conditions

Excludes2 at I50

Cardiac arrest (I46.-), neonatal cardiac failure (P29.0)

Excludes2 at I50.9

Fluid overload unrelated to congestive heart failure (E87.70)

The specificity here is usually available. An echocardiogram with an ejection fraction sits in most charts carrying this code, and the ejection fraction is what distinguishes systolic from diastolic failure.

2Code structure

Two axes inside the category, one instruction above it

I50.9 has no subdivisions. The category varies along type and acuity, and both are documented in the record far more often than they reach the code.

The type axis

Not specified

I50.9

This code

Left ventricular, type not further specified

I50.1

Systolic, meaning reduced ejection fraction

I50.2-

Diastolic, meaning preserved ejection fraction

I50.3-

Combined systolic and diastolic

I50.4-

Right heart failure

I50.81-

Biventricular

I50.82

High output

I50.83

End stage

I50.84

Other specified

I50.89

The acuity axis, on the systolic, diastolic, combined, and right-sided subcategories

Unspecified

0

Acute

1

Chronic

2

Acute on chronic

3

So a note reading acute on chronic diastolic heart failure produces a five-character code, and a note reading heart failure produces I50.9. Both describe the same patient at different documentation depths.

The instruction above the category reorders the claim. I50 carries a code-first note listing six conditions, and one of them applies to a large share of heart failure patients.

Hypertension with heart failure

The hypertensive heart disease code first, then the I50 code

Hypertension and chronic kidney disease with heart failure

The applicable hypertensive heart and kidney disease code first, then the I50 code

Heart failure following surgery

The post-procedural code first

Rheumatic heart failure

The rheumatic code first

Heart failure complicating abortion, ectopic or molar pregnancy

The obstetric code first

Heart failure following obstetric surgery or procedures

The obstetric code first

The hypertension pairing is bidirectional, and neither code stands alone. The hypertensive heart disease code presumes the causal relationship and carries the combination, but it does not say what kind of heart failure the patient has. The I50 code supplies that. So both codes appear, the hypertensive one first, and reporting either by itself leaves the claim incomplete.

3Clinical picture

Clinical findings documented under I50.9

A record supporting this code establishes heart failure without stating its type or acuity.

Respiratory

Dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea

Volume overload

Peripheral edema, weight gain, jugular venous distension, ascites

Examination

Pulmonary rales, third heart sound, hepatomegaly

Functional

Reduced exercise tolerance, fatigue, and functional class where recorded

Imaging and testing

Ejection fraction on echocardiography, chest radiograph findings, natriuretic peptide levels

Comorbidity

Hypertension, coronary disease, atrial fibrillation, chronic kidney disease, diabetes

Ejection fraction is the finding that moves the code, and it is usually the one already in the chart. A documented reduced ejection fraction supports systolic failure, and a preserved one supports diastolic, which takes the encounter out of I50.9 in either direction.

One caution about staging language. The Alphabetic Index carries a note that the American College of Cardiology and American Heart Association stages A through D are not the same thing as the New York Heart Association functional classes I through IV, and directs that stage B be coded by type as systolic or diastolic where known. Staging language in a note is not itself a code, but it is often a signal that the type is documented elsewhere.

4Documentation

What the chart must show

  • A provider-stated diagnosis of heart failure
  • Type, meaning systolic, diastolic, combined, or right-sided
  • Acuity, meaning acute, chronic, or acute on chronic
  • Ejection fraction, with the study date
  • Hypertension status, since it changes the sequencing
  • Chronic kidney disease and its stage, since that changes which hypertensive code leads
  • Whether the failure followed cardiac surgery, or has a rheumatic origin
  • An assessment and plan showing the condition was evaluated, addressed, or treated at this encounter

The failure mode on this code is not a missing test. It is a preserved problem-list entry. A patient carried on a problem list as CHF for years, with echocardiograms in the chart showing a reduced ejection fraction, still generates I50.9 every visit because the assessment repeats the problem-list wording.

5Decision guide

When to assign I50.9, and when not to

Heart failure or CHF, no type or acuity

I50.9

Left ventricular failure, no further detail

I50.1

Systolic heart failure, or reduced ejection fraction

The applicable I50.2- code with acuity

Diastolic heart failure, or preserved ejection fraction

The applicable I50.3- code with acuity

Combined systolic and diastolic failure

The applicable I50.4- code with acuity

Right heart failure

The applicable I50.81- code

Biventricular heart failure

I50.82

End-stage heart failure

I50.84

Hypertension with heart failure

The hypertensive heart disease code first, then the I50 code

Hypertension and CKD with heart failure

The applicable hypertensive heart and kidney code first, then the I50 code

Heart failure after cardiac surgery

The post-procedural code first

Rheumatic heart failure

The rheumatic code first

Cardiac arrest

I46.-, reportable alongside

Fluid overload unrelated to heart failure

E87.70, reportable alongside

Neonatal cardiac failure

P29.0

Query rather than default when an echocardiogram report with an ejection fraction sits in the chart, when the note says acute exacerbation without naming the type, and when hypertension appears in the problem list but the claim carries only an I50 code.

6Tabular list

Instructional notes at I50 and above

Code first at I50

Heart failure due to hypertension (I11.0)

Code first at I50

Heart failure due to hypertension with chronic kidney disease (I13.-)

Code first at I50

Heart failure following surgery (I97.13-)

Code first at I50

Rheumatic heart failure (I09.81)

Code first at I50

Heart failure complicating abortion or ectopic or molar pregnancy (O00 to O07, O08.8)

Code first at I50

Obstetric surgery and procedures (O75.4)

Excludes2 at I50

Cardiac arrest (I46.-), neonatal cardiac failure (P29.0)

Excludes2 at I50.9

Fluid overload unrelated to congestive heart failure (E87.70)

Six code-first conditions are the most of any code in this glossary, and the category carries no Excludes1 at all. That combination is unusual. It means the constraint on I50.9 is almost entirely about sequencing rather than about prohibited pairs.

Both notes at the category are Excludes2, so both are permissions. Cardiac arrest is not part of what heart failure describes, but a patient may have both, and both may be reported. The same is true of neonatal cardiac failure, which is worth noting because coders often read a newborn exclusion as an absolute bar.

The fluid overload note at the code line is also a permission. Fluid overload unrelated to congestive heart failure has its own code, and a patient documented with both may carry codes from each. What the note prevents is using the fluid overload code to describe heart failure itself.

7Comparison

Codes frequently confused with I50.9

I50.1

Descriptor

Left ventricular failure, unspecified

Use instead when

Left ventricular failure is documented without a type

I50.20 to I50.23

Descriptor

Systolic heart failure, unspecified, acute, chronic, acute on chronic

Use instead when

Reduced ejection fraction or systolic failure is documented

I50.30 to I50.33

Descriptor

Diastolic heart failure, by acuity

Use instead when

Preserved ejection fraction or diastolic failure is documented

I50.40 to I50.43

Descriptor

Combined systolic and diastolic heart failure, by acuity

Use instead when

Both are documented

I50.81-

Descriptor

Right heart failure, by acuity and including right failure due to left heart failure

Use instead when

Right-sided failure is documented

I50.82

Descriptor

Biventricular heart failure

Use instead when

Biventricular failure is documented

I50.83

Descriptor

High output heart failure

Use instead when

High output failure is documented

I50.84

Descriptor

End-stage heart failure

Use instead when

End-stage failure is documented

I50.89

Descriptor

Other heart failure

Use instead when

Another named form is documented

I11.0

Descriptor

Hypertensive heart disease with heart failure

Use instead when

Hypertension is present, sequenced ahead of the I50 code

I13.0, I13.2

Descriptor

Hypertensive heart and chronic kidney disease with heart failure, by CKD stage

Use instead when

Hypertension and CKD are both present

I09.81

Descriptor

Rheumatic heart failure

Use instead when

The failure is rheumatic in origin

I97.13-

Descriptor

Postprocedural heart failure

Use instead when

The failure followed surgery

I46.-

Descriptor

Cardiac arrest

Use instead when

Arrest occurred; reportable alongside

I42.-

Descriptor

Cardiomyopathy

Use instead when

Cardiomyopathy is the diagnosis

I51.7

Descriptor

Cardiomegaly

Use instead when

Cardiomegaly is documented without failure

E87.70

Descriptor

Fluid overload, unspecified

Use instead when

Fluid overload unrelated to heart failure is documented; reportable alongside

P29.0

Descriptor

Neonatal cardiac failure

Use instead when

The patient is a newborn

R06.02, R60.0

Descriptor

Shortness of breath, localized edema

Use instead when

Symptoms are documented without a heart failure diagnosis

The I11.0 row is the one that changes claims. It is not an alternative to I50.9. It is the code that precedes it.

8Claim context

Services commonly reported with I50.9

I50.9 supports primary care and cardiology evaluation and management, echocardiography, natriuretic peptide testing, chest imaging, chronic care management, and cardiac rehabilitation where a patient qualifies. On the inpatient side, it anchors a heart failure diagnosis-related group family whose weight depends on the acuity and the comorbidities reported alongside it, which is another reason the acuity character matters.

Natriuretic peptide testing and echocardiography are not governed by any of the twenty-three national laboratory determinations, so frequency and indication rules are set contractor by contractor. Serial echocardiography on a stable patient is a recurring review target, and the record needs a clinical question behind each study rather than an interval habit.

Device and advanced therapies for heart failure, including implantable defibrillators and ventricular assist devices, are governed by national coverage determinations with detailed clinical criteria including ejection fraction thresholds and functional class. Those criteria are documented in the coverage policy rather than in the diagnosis code, and a claim carrying I50.9 does not establish them. Check the applicable national determination directly before submitting device-related services, and the contractor determination for imaging and testing frequency.

9Risk adjustment

What I50.9 does to a risk score

The code pays, and the model now rewards saying more

I50.9 maps to the heart failure category that excludes end-stage and acute failure under the current model.

Its weight rose slightly in the move from the previous model version, and the current model reached full phase-in for payment year 2026.

Report it every year.

Risk adjustment does not carry a condition forward. A heart failure diagnosis captured last year contributes nothing to this year's score unless it is documented and reported again at a face-to-face encounter.

The model separated severity, which changed the incentive.

The previous model had a single congestive heart failure category. The current one carves end-stage and acute heart failure into their own categories, leaving I50.9 in the residual. Documenting end-stage heart failure when that is the clinical reality now routes to a different category than an unspecified code does, so specificity affects the score and not only the chart.

The audit pattern is the problem-list entry.

A heart failure code pulled from a problem list, with no assessment addressing it at the encounter, is what reviewers look for first. Because this condition is chronic and almost always present, it is also the one most likely to be carried forward without support.

Verify the category against the payment year.

The model renumbered categories in the transition, so an internal crosswalk built for an earlier payment year will show a different number for the same condition.

10Denials

Coding errors that cause denials

Reporting I50.9 when hypertension is also documented

Sequence the hypertensive heart disease code first, then the I50 code

Reporting the hypertensive heart disease code alone

Add the I50 code, since the combination code does not state the type

Coding I50.9 when an ejection fraction is documented

Assign the systolic, diastolic, or combined code as the study supports

Coding I50.9 when the note says acute exacerbation

Query for the type, then assign the acute on chronic code

Repeating a problem-list CHF entry year after year

Update the diagnosis as echocardiography and clinical course refine it

Dropping the cardiac arrest code on an assumed conflict

Report both, since that note is an Excludes2

Using the fluid overload code to describe heart failure

Assign the heart failure code, and report fluid overload only where unrelated

Coding I50.9 for a newborn

Assign P29.0

Reporting I50.9 with no assessment at the encounter

Report only when the record evaluates, addresses, or treats the condition

Relying on a pre-transition crosswalk for the risk adjustment category

Verify against the current payment year model file

11Sources

Where to verify I50.9

ICD-10-CM Official Guidelines for Coding and Reporting

The code first convention, the presumed relationship between hypertension and heart failure, and the criteria for reporting other diagnoses

ICD-10-CM Tabular List at I50 and at I11 and I13

The six code-first conditions, the Excludes2 notes, and the requirement that a heart failure type code accompany the hypertensive combination code

CMS ICD-10 code page and the FY 2026 files

Current code files, the annual addenda, and the full I50 subcategory structure

CMS Medicare Advantage rates and statistics

The current payment year model file and the heart failure categories, which were separated by severity in the current version

Medicare Coverage Database

The national determinations for heart failure device therapies, and your contractor's determinations for echocardiography and natriuretic peptide testing

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Last reviewed August 2026

This page is a free reference for billing and coding teams and is not coding, legal, or clinical advice. Code selection depends on the documentation in the record and on the policy of the payer being billed. Verify every code, instructional note, and sequencing rule against the current ICD-10-CM files and the Official Guidelines for Coding and Reporting for the applicable date of service. ICD-10-CM is maintained by the CDC's National Center for Health Statistics and published by CMS. CPT is a registered trademark of the American Medical Association. TruCare is not affiliated with CMS, NCHS, the AHA, or the AMA.

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