2027 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 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Q20.4 is a billable ICD-10-CM diagnosis code for double inlet ventricle. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 306 through 307. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 91 closely related codes. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cardiac and circulatory congenital anomalies.

Q20.4 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 191 for payment year 2027.

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 the other POA exempt codes in Congenital malformations of the circulatory system (Q20-Q28).

Medicare Risk Adjustment (HCC)Billing

Q20.4 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model, but it maps to payment categories in the other CMS models shown below.

CMS-HCC V28 (Medicare Advantage Payment Model)
Not mapped
no payment category in the model that pays 100% of MA risk scores
Prior Model (CMS-HCC V24)
Not mapped under V24
this diagnosis newly risk-adjusts under the V28 model
Part D (RxHCC)
RxHCC 191 — Ventricular Septal Defect and Major Congenital Heart Disorders
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

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
  • Dilatation of tricuspid annulus
  • 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
  • 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
  • Tricuspid leaflet fenestration
  • True cleft of left atrioventricular valve leaflet
  • Two atrioventricular valves in double inlet ventricle

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Q20.4: its own notes plus those printed at Q20 and Chapter 17. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Common ventricle
  • Cor triloculare biatriatum
  • Single ventricle

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Q20 Congenital malformations of cardiac chambers and connections applies to 9 codes
  • dextrocardia with situs inversus (Q89.3)
  • mirror-image atrial arrangement with situs inversus (Q89.3)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 17 (Q00-QA1) Congenital malformations, deformations and chromosomal abnormalities applies to 900 codes
  • inborn errors of metabolism (E70-E88)

Notes

General instructions on how these codes are used.

From Chapter 17 (Q00-QA1) Congenital malformations, deformations and chromosomal abnormalities applies to 900 codes
  • Codes from this chapter are not for use on maternal records

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name Q20.4, its category, or a range that includes it.

Use Additional Code 1

These codes say to use an additional code from the note, and Q20.4 is one of the codes named.

  • Q87.88 CTNNB1 syndrome
    congenital heart malformations (Q20.0-Q24.9) names Q20.0-Q24.9, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Q20.4Overview

What is the ICD-10 code for double inlet ventricle?

The ICD-10-CM code for double inlet ventricle is Q20.4 (sometimes written as Q204). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

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, 2026 through September 30, 2027.

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 0.9146 to 1.5457 depending on complications. Higher weights mean higher Medicare reimbursement.

Is Q20.4 a CC or MCC?

CMS lists Q20.4 as an MCC (major complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 91 closely related codes in its exclusion list.

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. The code appears in the Congenital malformations of the circulatory system (Q20-Q28) range of the CMS exempt list.

Does Q20.4 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage: Q20.4 maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 191 (Ventricular Septal Defect and Major Congenital Heart Disorders).