| Q20 | Congenital malformations of cardiac chambers and connections | NON-BILLABLE CODE |
| Q20.0 | Common arterial trunk | BILLABLE CODE |
| Q20.2 | Double outlet left ventricle | BILLABLE CODE |
| Q20.3 | Discordant ventriculoarterial connection | BILLABLE CODE |
| Q20.4 | Double inlet ventricle | BILLABLE CODE |
| Q20.5 | Discordant atrioventricular connection | BILLABLE CODE |
| Q20.6 | Isomerism of atrial appendages | BILLABLE CODE |
| Q20.8 | Other congenital malformations of cardiac chambers and connections | BILLABLE CODE |
| Q20.9 | Congenital malformation of cardiac chambers and connections, unspecified | BILLABLE CODE |
