Circulation : Clinical Summaries

Abstract

Brugada syndrome (BrS) is a hereditary cardiac disorder associated with an increased risk of fatal ventricular arrhythmias. BrS has been extensively studied at the molecular and cellular scales. However, the cardiac electrophysiological substrate that underlies the BrS ECG and supports ventricular arrhythmias in the intact heart of BrS patients has not been elucidated. This article reports the results of panoramic electrophysiological mapping using noninvasive ECG imaging in 25 BrS patients. The results indicate that the abnormal electrophysiological substrate is localized exclusively in the right ventricular outflow tract. The right ventricular outflow tract displays delayed activation, prolonged repolarization, and steep repolarization gradients. These findings reveal the existence of both abnormal repolarization and slow discontinuous conduction in the BrS substrate. Together, these properties provide conditions that promote sustained reentry. These observations have implications for the diagnosis and mechanism-based, targeted therapy of BrS arrhythmias. A related finding of clinical significance is the demonstrated capability of ECG imaging to differentiate BrS from right bundle-branch block based on differences in epicardial activation, repolarization, and electrogram morphologies. See p 1950. After the initial human implantation in 2000, transcatheter pulmonary valve (TPV) replacement with the Melody valve was introduced in the United States in 2007 through a prospective, multicenter Investigational Device Exemption trial. Early and short-term …