2026 ICD-10-CM Diagnosis Code Q20.4Double inlet ventricle

ICD-10-CM Codes›Q00-Q99›Q20-Q28›Q20

ICD-10-CM Q20.4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q20.4 is a billable ICD-10-CM diagnosis code for double inlet ventricle. 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
Q20.4
Billable Status
Yes — Valid for Submission
Code Describes
Double inlet ventricle
Short Description
Double inlet ventricle
Same as the full description in the CMS dataset.
Parent Code
Q20
Congenital malformations of cardiac chambers and connections

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ20-Q28Congenital malformations of the circulatory system
CategoryQ20Congenital malformations of cardiac chambers and connections
This CodeQ20.4Double inlet ventricle

Present on Admission (POA)Billing

Q20.4 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.

  • Abnormality of left atrioventricular valve chordae tendinae
  • Abnormality of left atrioventricular valve in double inlet ventricle
  • Abnormality of right atrioventricular valve chordae tendinae
  • Abnormality of right atrioventricular valve in double inlet ventricle
  • Absent left atrioventricular valve leaflets
  • Absent right atrioventricular valve leaflets
  • Accessory tissue on left atrioventricular valve leaflet
  • Arcade abnormality of left atrioventricular valve chordae
  • Common atrioventricular orifice in double inlet ventricle
  • Common ventricle
  • Congenital abnormality of left atrioventricular valve chordae tendinae in double inlet ventricle
  • Congenital abnormality of left atrioventricular valve in double inlet ventricle
  • Congenital abnormality of left atrioventricular valve papillary muscle
  • Congenital abnormality of right atrioventricular valve chordae tendinae in double inlet ventricle
  • Congenital abnormality of right atrioventricular valve in double inlet ventricle
  • Congenital abnormality of right atrioventricular valve leaflet in double inlet ventricle
  • Congenital abnormality of right atrioventricular valve papillary muscle
  • Congenital abnormality of right atrioventricular valve papillary muscle in double inlet ventricle
  • Congenital absence of left atrioventricular valve papillary muscle
  • Congenital absence of papillary muscle
  • Congenital anomaly of left-sided atrioventricular valve in double inlet ventricle
  • Congenital anomaly of right-sided atrioventricular valve in double inlet ventricle
  • Congenital cleft of cardiac valve
  • Congenital fusion of left atrioventricular valve papillary muscles
  • Congenital hypoplastic left atrioventricular valve papillary muscle
  • Congenital parachute malformation of left atrioventricular valve
  • Congenital parachute malformation of right atrioventricular valve
  • Double inlet left ventricle
  • Double inlet right ventricle
  • Double inlet to solitary ventricle of indeterminate morphology
  • Double inlet to ventricle of indeterminate morphology
  • Double inlet ventricle
  • Double orifice of left atrioventricular valve
  • Double orifice of right atrioventricular valve
  • Double orifice of right atrioventricular valve in double inlet ventricle
  • Ebstein's anomaly of left atrioventricular valve
  • Ebstein's anomaly of left atrioventricular valve in functionally univentricular heart
  • Functional single ventricle
  • Functionally univentricular heart
  • Hypoplasia of left atrioventricular valve annulus in double inlet ventricle
  • Hypoplasia of right atrioventricular valve annulus in double inlet ventricle
  • Left atrioventricular valve atresia
  • Left atrioventricular valve chordae to outlet septum
  • Left atrioventricular valve chordae too long
  • Left atrioventricular valve chordae too short
  • Left atrioventricular valve dysplasia
  • Left atrioventricular valve hypoplasia
  • Left atrioventricular valve leaflet abnormality
  • Left atrioventricular valve leaflet dysplasia
  • Left atrioventricular valve prolapse
  • Left atrioventricular valve stenosis
  • Left atrioventricular valve stenosis in double inlet ventricle
  • Overriding left atrioventricular valve
  • Overriding right atrioventricular valve
  • Right atrioventricular valve dysplasia
  • Right atrioventricular valve hypoplasia
  • Right atrioventricular valve leaflets absent in double inlet ventricle
  • Right atrioventricular valve stenosis
  • Single left ventricle
  • Single right ventricle
  • Solitary ventricle of indeterminate morphology
  • Straddling left atrioventricular valve
  • Straddling right atrioventricular valve
  • Straddling tricuspid valve
  • True cleft of left atrioventricular valve leaflet
  • Two atrioventricular valves in double inlet ventricle

Tabular List NotesGuidance

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

Inclusion Terms

  • Common ventricle
  • Cor triloculare biatriatum
  • Single ventricle

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.

    • Absence(of) (organ or part) (complete or partial)
      • septum
        • ventricular (congenital)
    • Absence(of) (organ or part) (complete or partial)
      • ventricular septum
    • Agenesis
      • septum
        • ventricular
    • Common
      • ventricle
    • Cor
      • triloculare
        • biatrium
    • Displacement, displaced
      • ventricular septum
        • with rudimentary ventricle
    • Double
      • inlet ventricle
    • Single
      • ventricle

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

Patient EducationClinical

Congenital Heart Defects

Congenital heart defects (CHDs) are problems with the structure of the heart. "Congenital" means that that the problems are present at birth. These defects happen when a fetus's heart doesn't develop normally during pregnancy. Congenital heart defects are the most common type of birth defect.

The full article covers:

  • What are congenital heart defects?
  • What causes congenital heart defects?
  • Who is more likely to have a baby with a congenital heart defect?
  • What are the symptoms of congenital heart defects?
  • What other problems do congenital heart defects cause?
  • How are congenital heart defects diagnosed?
  • What are the treatments for congenital heart defects?

Read the full article at MedlinePlus

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

Convert Q20.4 to ICD-9-CMHistory

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

ICD-9-CM
745.3 Common ventricle
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 Q20.4Overview

Is Q20.4 (Congenital malformations of cardiac chambers and connections) a billable code?

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

What MS-DRG does Q20.4 group to?

When double inlet ventricle 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 Q20.4 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 double inlet ventricle on inpatient claims.

What is the ICD-9 equivalent of Q20.4?

Under the General Equivalence Mappings, double inlet ventricle converts to ICD-9-CM 745.3 (common ventricle). 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.