2027 ICD-10-CM Diagnosis Code Q20.5Discordant atrioventricular connection
ICD-10-CM Codes›Q00-Q99›Q20-Q28›Q20
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- POA Exempt
- Chronic Condition
Q20.5 is a billable ICD-10-CM diagnosis code for discordant atrioventricular connection. 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 complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within 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.
Q20.5 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
Code Classification
Present on Admission (POA)Billing
Q20.5 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
Q20.5 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.
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.
- Abnormal atrioventricular connection
- Abnormal atrioventricular connection - biventricular
- Abnormal atrioventricular connection - univentricular
- Ambiguous atrioventricular connection
- Corrected transposition of great vessels
- Dilatation of tricuspid annulus
- Discordant atrioventricular connection
- Discordant ventriculoarterial connection
- Double outlet ventriculoarterial connections
- Doubly committed ventricular septal defect in double outlet ventriculoarterial connection
- Ebstein's anomaly
- Ebstein's anomaly of left sided tricuspid valve with discordant atrioventricular connections
- L - transposition of the great vessels
- Tricuspid leaflet fenestration
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to Q20.5: 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.
- Corrected transposition
- Levotransposition
- Ventricular inversion
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
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.
Notes
General instructions on how these codes are used.
- 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 Q20.5, its category, or a range that includes it.
Use Additional Code 1
These codes say to use an additional code from the note, and Q20.5 is one of the codes named.
- Q87.88 CTNNB1 syndrome
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Corrected transposition Q20.5
ventricular Q20.5
Levotransposition Q20.5
Transposition (congenital) See Also: Malposition, congenital;
corrected Q20.5
Ventricle, ventricular See Also: condition;
inversion Q20.5
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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 Q20.5 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About Q20.5Overview
What is the ICD-10 code for discordant atrioventricular connection?
The ICD-10-CM code for discordant atrioventricular connection is Q20.5 (sometimes written as Q205). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is Q20.5 (Congenital malformations of cardiac chambers and connections) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report discordant atrioventricular connection on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does Q20.5 group to?
When discordant atrioventricular connection 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 Q20.5 a CC or MCC?
CMS lists Q20.5 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 91 closely related codes in its exclusion list.
Is Q20.5 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 discordant atrioventricular connection on inpatient claims. The code appears in the Congenital malformations of the circulatory system (Q20-Q28) range of the CMS exempt list.
Does Q20.5 risk-adjust for Medicare Advantage payment?
Not for Medicare Advantage: Q20.5 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).
