Right ventricular electromechanical abnormalities in Brugada syndrome: is this a cardiomyopathy?

Abstract

Brugada syndrome (BrS) has been often described as a purely electrical disease. However, current dogma surrounding this concept has shifted to accept that BrS is associated with structural abnormalities. Brugada syndrome is now associated with epicardial surface and interstitial fibrosis, reduced gap junction expression, increased collagen, and reduced contractility. The ventricular arrhythmias observed in BrS have been linked to an arrhythmogenic substrate (AS) located rather consistently in the right ventricular outflow tract, sparking much debate as to the significance of this anatomical position. The size of the AS is dynamic and can be altered due to a number of factors. A larger AS is associated with reduced contractility, and this impaired mechanical function may be responsible for syncopal episodes in BrS patients in the absence of arrhythmic events. While BrS is generally regarded as a channelopathy, recent studies have now identified also mutations in genes encoding for sarcomeric proteins to be associated with BrS. Future studies should evaluate electromechanical coupling in BrS, including calcium handling and sarcomeric alterations, and evaluate whether BrS should be classified as a cardiomyopathy.