Q20.4 Double inlet ventricle

Billable ICD-10-CM code, FY2026. Acts as a Major Complication or Comorbidity (MCC) as a secondary diagnosis. Exempt from present-on-admission (POA) reporting.

Applicable to

• Common ventricle
• Cor triloculare biatriatum
• Single ventricle

Applies from Q20 Congenital malformations of cardiac chambers and connections

Excludes1 (never code together)

• dextrocardia with situs inversus (Q89.3)
• mirror-image atrial arrangement with situs inversus (Q89.3)

Risk adjustment (HCC)

• RxHCC V08: HCC 191 — Ventricular Septal Defect and Major Congenital Heart Disorders

MS-DRG index

Defines the logic of DRG(s) 306-307 in MDC 05.

Approximate ICD-9-CM (GEMs)

• 745.3 Common ventricle

Code annotations containing back-references to Q20.4

Back-references to Q20

• Code Also: I27.21 Secondary pulmonary arterial hypertension ("congenital heart disease (Q20-Q28)")
• Type 2 Excludes: P29 Cardiovascular disorders originating in the perinatal period ("congenital malformations of the circulatory system (Q20-Q28)")
• Code Also: Z71.87 Encounter for pediatric-to-adult transition counseling ("congenital malformations of the circulatory system (Q20-Q28)")

Diagnosis Index entries for Q20.4

• 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

Nearby codes

• Q20 Congenital malformations of cardiac chambers and connections
• Q20.0 Common arterial trunk
• Q20.1 Double outlet right ventricle
• Q20.2 Double outlet left ventricle
• Q20.3 Discordant ventriculoarterial connection
• Q20.4 Double inlet ventricle (this code)
• Q20.5 Discordant atrioventricular connection
• Q20.6 Isomerism of atrial appendages
• Q20.8 Other congenital malformations of cardiac chambers and connections
• Q20.9 Congenital malformation of cardiac chambers and connections, unspecified