| Electrocardiographic findings | Points |
| QTc | |
| >480 ms | 3 |
| 460–470 ms | 2 |
| 450 ms (male) | 1 |
| Torsade de pointe | 2 |
| T wave alternans | 1 |
| Notched T wave in three leads | 1 |
| Low heart rate for age | 0.5 |
| Clinical findings | |
| Syncope | |
| With stress | 2 |
| Without stress | 1 |
| Congenital deafness | 0.5 |
| Family history | |
| Long QT syndrome | 1 |
| Unexplained sudden death | 0.5 |
| Total* | |
↵* 2–3 points=intermediate probability of long QT syndrome; >4 points=high probability of long QT syndrome.7