KCNJ2 and Ventricular arrhythmia: Noticeably, the ECG during exercise testing is also different for both groups: ventricular arrhythmias appear early, stop at the peak of exercise to finally reappear after the end of exercise for KCNJ2-mutated patients with CPVT, while in other CPVT patients they appear early, increase to reach the maximum at peak and stop at rest.