Objective To investigate clinical symptoms, episodes of arrhythmias and its therapy in patients with Brugada syndrome treated with implantable cardioverter-defibrillator (ICD).

Methods Five patients with concealed Brugada syndrome (all male, mean age 41.6±10.14 years) were treated with single-chamber ICD and followed up every three months. The time of onset, type of arrhythmia, treatments and its results of the episodes were investigated according to the data logs of the ICD.

Results The diagnosis of Brugada syndrome was made according to sodium channel blocker provocation test in four patients (2 by ajmaline, 2 by propafenone), and screen of new praecordial leads system in another case. Episodes of syncope in all patients and ventricular fibrillation in four cases were documented before ICD therapy. During electrophysiological study, ventricular fibrillation could be induced in three patients. During a follow-up of 22±18 months, 75 episodes of ventricular fibrillation were documented. Among them 61 were terminated by 86 shocks successfully, 14 stopped spontaneously. One patient still experienced 4 episodes of syncope because of his increased defibrillation threshold. One patient had 26 times inappropriate shocks due to atrial fibrillation, which disappeared after we adjusted the protocol of the ICD. Another one had two episodes of syncope though no event was recorded in his ICD. Because the tilt test reached positive result, the diagnosis of vasovagal syncope was made.

Conclusion ICD implantation is a necessary and effective therapy for high risk patients with Brugada syndrome, and should be followed up regularly and programmed appropriately because of increased defibrillation threshold or inappropriate shocks.