Q21.23

Billable

Complete atrioventricular septal defect

HCC Category Mapping

RxHCCHCC 191 — Congenital Heart/Circulatory Disorders and Fontan Circulation

0.000

What This Code Means

A birth defect where there is a complete abnormal opening in the wall between all four heart chambers, with a single common atrioventricular valve instead of separate mitral and tricuspid valves.

Coding Tips

•Complete AVSD is the most severe form; document the presence of a common atrioventricular valve and any associated valve regurgitation
•Often associated with Down syndrome; review documentation for chromosomal abnormalities

Clinical Significance

Complete atrioventricular septal defect represents the most severe form with a large central hole affecting all four heart chambers and a single common atrioventricular valve. This condition creates significant hemodynamic abnormalities requiring early surgical intervention to prevent irreversible pulmonary vascular disease.

Documentation Requirements

✓Echocardiographic confirmation of complete defect with common valve
✓Assessment of degree of valve regurgitation
✓Evaluation of pulmonary vascular resistance
✓Associated cardiac anomalies documentation
✓Signs of congestive heart failure
✓Surgical intervention timing and outcomes
✓Current cardiac function and exercise tolerance
✓Associated Down syndrome documentation if present

Commonly Confused Codes

Q21.21 — partial atrioventricular septal defect Q21.22 — transitional atrioventricular septal defect Q21.0 — ventricular septal defect Q20.4 — double inlet ventricle Q22.3 — other congenital malformations of pulmonary valve

Code Hierarchy

└Q21Congenital malformations of cardiac septa └Q21.2Atrioventricular septal defect └Q21.23Complete atrioventricular septal defect

└Q21.23Complete atrioventricular septal defect