Abstract
Previous reports have demonstrated that the implantable cardioverter defibrillator is the only proven treatment to prevent sudden death in patients with Brugada syndrome (BS). However, several recent reports have shown that oral quinidine (QND) administration prevented ventricular fibrillation (VF) storm and VF induction by programmed ventricular stimulation (PVS); thus, it might be a potential alternative therapy for BS. We investigated the effects of intravenous administration of QND on the refractoriness and the action potential duration restitution kinetics at the right ventricular outflow tract (RVOT) in patients with BS. The subjects of this study included 5 asymptomatic patients with BS. One patient exhibited Brugada-type-1 ST-segment elevation, three patients exhibited type-2 ST-segment elevation, and the other exhibited type-3 ST-segment elevation. All patients had inducible VF at baseline PVS. In 4 of 5 patients, VF could not be induced after intravenous administration of QND. In these 4 patients, QND increased the effective refractory period (ERP) of the RVOT and decreased the maximum slope of the action potential duration restitution curve of the RVOT. Intravenous QND test might be useful for evaluating the efficacy of oral QND to prevent sudden cardiac death/ VF in BS.
