Hydroquinidine Versus Placebo in Patients With Brugada Syndrome (Quidam)

• To determine whether hydroquinidine enhances time length before arisen of an appropriate shock registered on the automatic implantable defibrillator (meaning due to ventricular arrhythmia) [ Time Frame: 3 years after patient randomization ]
  

• To evaluate number and frequency of inappropriate shock with and without hydroquinidine [ Time Frame: 3 years after patient randomization ]
  
• To evaluate the number of tachycardia or of ventricular fibrillations detected by the defibrillator but not having required any treatment [ Time Frame: 3 years after patient randomization ]
  
• To evaluate number of syncope reported by the patient but for which no ventricular arrhythmias has been detected by the defibrillator [ Time Frame: 3 years after patient randomization ]
  
• To evaluate the number and frequency of adverse events appeared under hydroquinidine treatment [ Time Frame: 3 years after patient randomization ]
  
• To evaluate interest of the electrophysiological exploration for determining chances of success of an hydroquinidine [ Time Frame: 3 years after patient randomization ]
  

During this double-blind randomized cross-over study, patient will receive during 18 months treatment 1 (hydroquinidine or placebo) and, after 7 days of wash-out, patient will receive treatment 2 (meaning for example hydroquinidine if treatment 1 was placebo). Time length before arisen of an appropriate shock registered on the defibrillator (meaning due to ventricular arrhythmia) will be assessed during treatment 1 period and treatment 2 period.We hypothesized that hydroquinidine administration will enhance time length before arisen of an appropriate shock and thus mean that hydroquinidine administration can prevent heart from appearance of ventricular arrhythmia. Patient's defibrillator recordings will be analysed every 6 months plus when patient experiences an ICD shock. If the shock delivered by the ICD is appropriate and happens during treatment 1 period, patient will switch to treatment 2 period after 7 days of wash-out. If the shock delivered by the ICD is appropriate and happens during treatment 2 period, study will be finished for this patient.Before starting the study, each patient will test which dose of hydroquinidine she/he requires to have an hydroquinidine concentration in her/his blood included between 3 and 6 µmol/L.

Planned enrollment: 200 subjects (60 being symptomatic with histories of aborted sudden cardiac death or of ventricular fibrillation, 70 being symptomatic with histories of syncope considered as of arrhythmic origin, 70 being asymptomatic with a spontaneous type 1 ECG and a positive electrophysiological exploration)