Contraction delay of the RV outflow tract in patients with Brugada syndrome is dependent on the spontaneous ST-segment elevation pattern

BackgroundA growing body of evidence suggests that the arrhythmogenic substrate underlying Brugada syndrome (BrS) is located in the right ventricular outflow tract (RVOT), and electrophysiological abnormalities recently evidenced most commonly concur in conduction slowing. Also, imaging studies reported wall motion abnormalities of the RVOT in patients with BrS, with a various extent of RV remodeling. However, there are no data regarding a potential relationship between electrophysiological alterations and contraction abnormalities in BrS.ObjectiveWe aimed to assess (1) the potential relationship between contraction delays of the RV quantified by phase analysis of equilibrium radionuclide angiography (ERNA), and the spontaneous ST-segment elevation pattern; and (2) to evidence RV remodeling in patients with BrS.MethodsSeventy patients with BrS and 18 control subjects were included in the study. For the purpose of the study, the spontaneous ST-segment elevation pattern was graded simultaneously to ERNA acquisition. RV contraction delays and amplitude were assessed using multiharmonic phase analysis of ERNA, and ventricular volumes and ejection fraction were assessed using gated blood-pool single photon emission computed tomography.ResultsRVOT contraction was delayed in patients with BrS, and RV contraction heterogeneity increased according to the pattern of ST-segment elevation, without impairment of the amplitude of contraction. RV volumes were greater in patients with BrS compared with control subjects, without impairment of the ejection fraction, whatever the ST-segment elevation pattern or the magnitude of contraction heterogeneity.ConclusionIn patients with BrS, we found a relationship between RV contraction heterogeneity and ST-segment pattern, providing evidence of a functional modulation of the arrhythmogenic substrate.