Low-Dose Quinidine Effectively Reduced Shocks in Brugada Syndrome Patients with an Implantable Cardioverter Defibrillator: A Chinese Case Series Report.

Background: Only implantable cardioverter defibrillators (ICD) have been proven to prevent sudden cardiac death (SCD) in patients with Brugada syndrome (BrS). However, ICD discharge, whether appropriate or inappropriate, leads to impaired quality of life and even increases rehospitalization. Quinidine might prevent the recurrence of ventricular arrhythmia (VA); however, the effect of low-dose quinidine for preventing spontaneous arrhythmias remains less clear. Methods: In our cardiology center, 10 confirmed patients with BrS (all men, mean age 38.7 +/- 6.72 years) who underwent appropriate ICD shocks due to recurrent VAs were treated with quinidine (<= 200 mg/day) and followed regularly. Results: All the patients underwent ICD shocks due to ventricular tachycardia (VT)/ventricular fibrillation (VF) before taking quinidine. A 24-hour distribution of VT/VF demonstrated that most of the events occurred in the sleeping time from 22:00 to 8:00. Quinidine prevented recurrence of VAs in nine patients. The other one patient took quinidine discontinuously because of anxiety suffered from less episodes of VA, and after psychological guidance, he took quinidine 200 mg/day and experienced no VA episodes from then on. In our series, only one patient suffered leukopenia related to quinidine. No other side effect was observed. Conclusions: Quinidine with a very low dose (<= 200 mg/day) well controlled VT/VF recurrence for a long-term period in Chinese patients with BrS. Administration (at 21:00) according to the circadian distribution of VT/VF episodes might increase the efficiency and improve the patient's tolerance.