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ICD-10-CM 2027 diagnosis code

I34.9Nonrheumatic mitral valve disorder, unspecified

✓ Billable / specific

I34.9 is a valid, billable ICD-10-CM code for nonrheumatic mitral valve disorder, unspecified. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About I34.9

I34.9 is the ICD-10-CM diagnosis code for nonrheumatic mitral valve disorder, unspecified. It belongs to category I34 (nonrheumatic mitral valve disorders), block I30-I5A (other forms of heart disease) and chapter 9 (diseases of the circulatory system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within I34, choose I34.9 (Nonrheumatic mitral valve disorder, unspecified) only when documentation doesn't support a more specific option: nonrheumatic mitral (valve) insufficiency (I34.0), nonrheumatic mitral (valve) prolapse (I34.1), nonrheumatic mitral (valve) stenosis (I34.2) and other nonrheumatic mitral valve disorders (I34.8).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 306 (Cardiac Congenital and Valvular Disorders with MCC, relative weight 1.546) and DRG 307 (Cardiac Congenital and Valvular Disorders without MCC, relative weight 0.9148), in MDC 05 (Diseases and Disorders of the Circulatory System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 424.0 (mitral valve disorders).

Notes that apply from higher levels

Instructions written at a parent level also apply to I34.9.

› From I34 Nonrheumatic mitral valve disorders
Excludes1
  • mitral valve disease (I05.9)
  • mitral valve failure (I05.8)
  • mitral valve stenosis (I05.0)
  • mitral valve disorder of unspecified cause with diseases of aortic and/or tricuspid valve(s) (I08.-)
  • mitral valve disorder of unspecified cause with mitral stenosis or obstruction (I05.0)
  • mitral valve disorder specified as congenital (Q23.2, Q23.9)
  • mitral valve disorder specified as rheumatic (I05.-)

Broader instructions also apply from Chapter 9: Diseases of the circulatory system.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to I34.9.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 424.0Mitral valve disordersapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about I34.9

Is I34.9 billable?

Yes. I34.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can I34.9 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict I34.9 as a principal diagnosis.

Is I34.9 a CC or MCC?

No. I34.9 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does I34.9 group to?

I34.9 is used in the MS-DRG v44.0 logic for MS-DRG 306 (Cardiac Congenital and Valvular Disorders with MCC) and MS-DRG 307 (Cardiac Congenital and Valvular Disorders without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for I34.9?

The CMS General Equivalence Mappings map I34.9 to ICD-9-CM 424.0.