Surface ECG characteristics of ventricular tachyarrhythmias before degeneration into ventricular fibrillation in patients with Brugada-type ECG.

This study was designed to evaluate whether the right ventricular outflow tract (RVOT) is the arrhythmogenic focus in Brugada syndrome. We enrolled 45 patients with Brugada-type ECG who underwent programmed ventricular stimulation and inducible ventricular fibrillation (VF). In 25 of these 32 patients, repetitive VT was observed before degeneration into VF. The QRS morphology of surface ECG and intracardiac electrograms were evaluated to determine the origin of the ventricular tachycardia (VT) that degenerated into VF. The VT morphology was a left bundle branch block pattern with an inferior axis in 22 of 28 VTs and the intracardiac conduction sequence during VT revealed activation from the RVOT to the RV apex in these 22 VTs. The majority of the patients with Brugada syndrome showed repetitive VT originating from the RVOT that degenerated into VF. The RVOT may be an arrhythmogenic focus in patients with Brugada syndrome.