2026 ICD-10-CM Diagnosis Code I34.1Nonrheumatic mitral (valve) prolapse

ICD-10-CM Codes›I00–I99›I30-I5A›I34

ICD-10-CM I34.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I34.1 is a billable ICD-10-CM diagnosis code for nonrheumatic mitral (valve) prolapse. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 306 through 307. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nonrheumatic and unspecified valve disorders.

This medical diagnosis code is frequently used in Cardiology medical specialties to designate conditions such nonrheumatic valve disorders - mitral valve disorders.

Code Identity

ICD-10-CM Code
I34.1
Billable Status
Yes — Valid for Submission
Code Describes
Nonrheumatic mitral (valve) prolapse
Short Description
Nonrheumatic mitral (valve) prolapse
Same as the full description in the CMS dataset.
Parent Code
I34
Nonrheumatic mitral valve disorders

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI30-I5AOther forms of heart disease
CategoryI34Nonrheumatic mitral valve disorders
This CodeI34.1Nonrheumatic mitral (valve) prolapse

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Arrhythmogenic bileaflet mitral prolapse
  • Degenerative mitral valve prolapse
  • Familial mitral valve prolapse
  • Hypogonadism with mitral valve prolapse and intellectual disability syndrome
  • Mitral cusp prolapse
  • Mitral valve anterior leaflet prolapse
  • Mitral valve posterior leaflet prolapse
  • Mitral valve prolapse
  • Mitral valve prolapse syndrome
  • Non-rheumatic mitral valve prolapse
  • Rheumatic mitral valve prolapse

Tabular List NotesGuidance

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

Inclusion Terms

  • Floppy nonrheumatic mitral valve syndrome

Type 1 Excludes

  • Marfan's syndrome Q87.4

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.

    • Floppy
      • nonrheumatic mitral valve syndrome
    • Prolapse, prolapsed
      • mitral (valve)
    • Syndrome
      • floppy
        • mitral valve

Clinical ClassificationClinical

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

CCSR CIR003
Nonrheumatic and unspecified valve disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Mitral Valve Prolapse

    abnormal protrusion or billowing of one or both of the leaflets of mitral valve into the left atrium during systole. this allows the backflow of blood into left atrium leading to mitral valve insufficiency; systolic murmurs; or cardiac arrhythmia.

Patient EducationClinical

Mitral Valve Prolapse

The mitral valve is one of the four valves in your heart. Heart valves have flaps that open and close. The flaps make sure that blood flows in the right direction through your heart and to the rest of your body. When your heart beats, the flaps open to let blood through.

The full article covers:

  • What is the mitral valve?
  • What is mitral valve prolapse (MVP)?
  • Who is more likely to develop mitral valve prolapse (MVP)?
  • What are the symptoms of mitral valve prolapse (MVP)?
  • What other problems can mitral valve prolapse (MVP) cause?
  • How is mitral valve prolapse (MVP) diagnosed?
  • What are the treatments for mitral valve prolapse (MVP)?
  • Can mitral valve prolapse be prevented?

Read the full article at MedlinePlus

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

Convert I34.1 to ICD-9-CMHistory

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

ICD-9-CM
424.0 Mitral valve disorder
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 I34.1Overview

Is I34.1 (Nonrheumatic mitral valve disorders) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report nonrheumatic mitral (valve) prolapse on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I34.1 group to?

When nonrheumatic mitral (valve) prolapse is the principal diagnosis on an inpatient stay, it groups to MS-DRG 306, 307, with relative weights from 0.9132 to 1.5758 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of I34.1?

Under the General Equivalence Mappings, nonrheumatic mitral (valve) prolapse converts to ICD-9-CM 424.0 (mitral valve disorder). 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.