2026 ICD-10-CM Diagnosis Code Q24.2Cor triatriatum

ICD-10-CM Codes›Q00-Q99›Q20-Q28›Q24

ICD-10-CM Q24.2
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q24.2 is a billable ICD-10-CM diagnosis code for cor triatriatum. 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. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cardiac and circulatory congenital anomalies.

Code Identity

ICD-10-CM Code
Q24.2
Billable Status
Yes — Valid for Submission
Code Describes
Cor triatriatum
Short Description
Cor triatriatum
Same as the full description in the CMS dataset.
Parent Code
Q24
Other congenital malformations of heart

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ20-Q28Congenital malformations of the circulatory system
CategoryQ24Other congenital malformations of heart
This CodeQ24.2Cor triatriatum

Present on Admission (POA)Billing

Q24.2 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cor triatriatum
  • Cor triatriatum with some pulmonary veins to proximal chamber draining to left atrium
  • Cor triatriatum with some pulmonary veins to proximal chamber draining to right atrium and others connecting directly to left atrium
  • Divided left atrium
  • Divided left atrium with all pulmonary veins to proximal chamber and then to left atrium
  • Divided left atrium with all pulmonary veins to proximal chamber and then to left atrium with additional pulmonary venous chamber communication
  • Divided left atrium with all pulmonary veins to proximal chamber and then to left atrium with additional pulmonary venous chamber communication to right atrium
  • Divided left atrium with all pulmonary veins to proximal chamber and then to left atrium with additional pulmonary venous chamber extracardiac communication
  • Divided left atrium with all pulmonary veins to proximal chamber without communication to left atrium
  • Divided left atrium with all pulmonary veins to proximal chamber without communication to left atrium with pulmonary venous chamber communication to right atrium
  • Divided left atrium with nonrestrictive outlet of proximal chamber to left atrium
  • Divided left atrium with some pulmonary veins to proximal chamber
  • Divided left atrium with some pulmonary veins to proximal chamber draining to left atrium and others connecting anomalously
  • Divided left atrium with some pulmonary veins to proximal chamber draining to left atrium and others connecting directly to left atrium
  • Divided left atrium with some pulmonary veins to proximal chamber draining to right atrium
  • Divided left atrium with some pulmonary veins to proximal chamber draining to right atrium and others connecting anomalously
  • Divided right atrium

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.

    • Cor
      • triatriatum, triatrium

Clinical ClassificationClinical

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

CCSR MAL001
Cardiac and circulatory congenital anomalies
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Cor Triatriatum

    a malformation of the heart in which the embryonic common pulmonary vein was not incorporated into the left atrium leaving behind a perforated fibromuscular membrane bisecting the left atrium, a three-atrium heart. the opening between the two left atrium sections determines the degree of obstruction to pulmonary venous return, pulmonary venous and pulmonary arterial hypertension.

  • Cor Triatriatum

    a rare congenital abnormality of the heart characterized by the presence of three atria. the right or left atrium is divided into two parts by fibromuscular tissue or a membrane. it may be associated with other heart congenital abnormalities.

Patient EducationClinical

Aneurysms

An aneurysm is a bulge or "ballooning" in the wall of an artery. Arteries are blood vessels that carry oxygen-rich blood from the heart to other parts of the body. If an aneurysm grows large, it can burst and cause dangerous bleeding or even death.

Read the full article at MedlinePlus

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

Convert Q24.2 to ICD-9-CMHistory

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

ICD-9-CM
746.82 Cor triatriatum
Exact Match The mapping is direct, with no qualifiers.

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 Q24.2Overview

Is Q24.2 (Other congenital malformations of heart) a billable code?

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

What MS-DRG does Q24.2 group to?

When cor triatriatum 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.

Is Q24.2 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for cor triatriatum on inpatient claims.

What is the ICD-9 equivalent of Q24.2?

Under the General Equivalence Mappings, cor triatriatum converts to ICD-9-CM 746.82 (cor triatriatum). The mapping is a direct match.

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.