| CHD anatomy* |
| I: Simple |
| Native disease |
| Isolated small ASD |
| Isolated small VSD |
| Mild isolated pulmonic stenosis |
| Repaired conditions |
| Previously ligated or occluded ductus arteriosus |
| Repaired secundum ASD or sinus venosus defect without significant residual shunt or chamber enlargement |
| Repaired VSD without significant residual shunt or chamber enlargement |
| II: Moderate complexity |
| Repaired or unrepaired conditions |
| Aorto-left ventricular fistula |
| Anomalous pulmonary venous connection, partial or total |
| Anomalous coronary artery arising from the pulmonary artery |
| Anomalous aortic origin of a coronary artery from the opposite sinus |
| AVSD (partial or complete, including primum ASD) |
| Congenital aortic valve disease |
| Congenital mitral valve disease |
| Coarctation of the aorta |
| Ebstein anomaly (disease spectrum includes mild, moderate, and severe variations) |
| Infundibular right ventricular outflow obstruction |
| Ostium primum ASD |
| Moderate and large unrepaired secundum ASD |
| Moderate and large persistently patent ductus arteriosus |
| Pulmonary valve regurgitation (moderate or greater) |
| Pulmonary valve stenosis (moderate or greater) |
| Peripheral pulmonary stenosis |
| Sinus of Valsalva fistula/aneurysm |
| Sinus venosus defect |
| Subvalvar aortic stenosis (excluding HCM; HCM not addressed in these guidelines) |
| Supravalvar aortic stenosis |
| Straddling atrioventricular valve |
| Repaired tetralogy of Fallot |
| VSD with associated abnormality and/or moderate or greater shunt |
| III: Great complexity (or complex) |
| Cyanotic congenital heart defect (unrepaired or palliated, all forms) |
| Double-outlet ventricle |
| Fontan procedure |
| Interrupted aortic arch |
| Mitral atresia |
| Single ventricle (including double inlet left ventricle, tricuspid atresia, hypoplastic left heart, any other anatomic abnormality with a functionally single ventricle) |
