Table 1.
Summary of clinical presentations
| Case number | Family number | Age at presentation (years) | Clinical presentation | ECG | Provocative testing | Number of asymptomatic, heterozygous relatives |
|---|---|---|---|---|---|---|
| 1 | 1 | 2.5 | VF/TdP with exertion | Normal | Not performed | 24 (same family) |
| 2 | 1 | 3.5 | VF/TdP with exertion | QTc 494 ms | EST: PVCs | |
| 3 | 2 | 9 | AVR, NSVT, and TdP with syncope | QTc 475 ms | Isoproterenol: polymorphic PVCs | 2 |
| 4 | 3 | 12 | VF while playing outside | Low voltages and flat t-waves with normal QTc | EST: monomorphic PVCs from RVOT | 2 |
| 5 | 4 | 22 | VF/TdP while walking and after an argument | QTc 464 ms | Isoproterenol: prolonged QTc | 2 |
| 6 | 5 | 31 | VF after an argument; history of recurrent syncope since age <15 | QTc 464 ms with notched T-waves on one ECG | Isoproterenol: prolonged QTc from normal to 520 ms with subsequent polymorphic VT | N/A |
| 7 | 6 | 12 | Recurrent syncope | QTc 460 ms | EST: PVCs and bi-directional couplets | N/A |
| 8 | 7 | 7 | Sudden death | Not performed | Not performed | 7 (same family) |
AVR, accelerated ventricular rhythm; EST, exercise stress test; N/A, no data available; NSVT, non-sustained ventricular tachycardia; QTc, corrected QT interval; TdP, torsade de pointes; VF, ventricular fibrillation.