Exercise ability in individual diagnostic groups
| Exercise ability | I | II | III | IV |
| PA-IVS | 4 | 1 | 2 | 0 |
| PA-VSD | 6 | 2 | 15 | 2 |
| Complex PA | 2 | 2 | 8 | 0 |
| Total | 12 | 5 | 25 | 2 |
IVS, intact interventricular sptum; PA, pulmonary atresia; VSD, ventricular septal defect. For exercise ability grades see text.