Table 5.
Mutations were identified and therapy was initiated in 11 children, including 2 siblings, affected by Long QTc in the screening ECG and Holter ECG.
| SEX | MUTATION | Familiarity | QTc ms (ECG) | QTc ms (ECG Holter) |
Therapy | Dosage |
|---|---|---|---|---|---|---|
| F | SCN5A (LQT3; c.647C>T) | No | 427 | 438 | Propranolol | 2 mg/kg, tid |
| F | KCNH2 (LQT2) | Father | 458 | 461 | Propranolol | 20 mg |
| F | KCNH2 (LQT2; c.1196C>T) | No | 438 and short PR | - | - | - |
| F | KCNH2 (LQT2; c.3367G>C) | No | 452 | 462 | Propranolol | 3 mg/kg, tid |
| F | KCNH2 (LQT2; c.2560T>G), SCN5A (LQT3; c.5845G>A) | No | - | - | - | - |
| F | KCNQ1 (polymorphism SCN5A-H558R, KCNH2-K897K, e KCNE1-S38G) | No | 448 | 465 | Propranolol | 2 mg/kg, tid |
| F | KCNQ1 (LQT1) | Mother | NA | NA | Nadolol | 1.5 mg/Kg/day |
| F | KCNQ1 (LQT1) | Mother and maternal grandfather | NA | NA | - | - |
| M | KCNQ1 (LQT1) | Mother and sister | 434 | 465 | Propranolol | ¾ + ½ + ½ |
| M * | KCNQ1 (LQT1) | Father (asymptomatic, QTc in the norm) |
NA | NA | Nadolol | 1 mg/Kg, qd |
| M * | KCNQ1 (LQT1) | Father (asymptomatic, QTc in the norm) |
NA | NA | Nadolol | 1 mg/Kg, qd |
* brothers. Legend: qd, once a day; tid, three times a day; NA, not available.