Introduction. Brugada syndrome (BrS) is a cardiac channelopathy characterized by a distinctive ECG pattern, either spontaneous or drug-induced, and a high risk of sudden arrhythmic events. Linked to conduction delay in the right ventricular outflow tract (RVOT) epicardium, BrS can be assessed noninvasively using ECG imaging (ECGi). Despite clinical recognition, the pathophysiological differences between spontaneous and induced BrS patterns remain unclear, hindering risk stratification. This study investigates ECGi-derived activation times (ATs) in BrS patients with spontaneous and induced patterns, compared to healthy controls.
Methods. ECGi data were acquired from 26 patients and volunteers at Hospital Clínico Universitario Lozano Blesa (Zaragoza, Spain) using the Acorys Mapping System, Corify Care SL. The population included 9 healthy controls (40±13 years) and 15 BrS patients, 7 with a spontaneous (BrS1, 53±7 years) and 9 with an induced (BrS2, 58±9 years) type 1 pattern. Epicardial unipolar electrograms (EGMs) reconstructed from 128-electrode body surface potential maps (BSPMs) and estimated 3D biventricular meshes were processed. The QRS width (QRSw) and total AT (TAT) were calculated from BSPMs and EGMs, respectively. The ventricles were segmented into 16 regions for AT and CV regional analysis.
Results. Higher values of QRSw (BrS1: 140±21 ms; BrS2: 127±18 ms, Healthy: 110±13 ms) and TAT (BrS1: 107±28 ms; BrS2: 96±9 ms; Healthy: 80±15 ms) were observed in BrS patients vs controls (p<0.05). Regional analysis suggested delayed conduction in the RVOT region, with significantly higher values of 90th percentile of AT in BrS groups (BrS1: 101±25 ms; BrS2: 94±16 ms, Healthy: 67±19 ms; BrS1 vs Healthy, p<0.05). Differences in AT and CV between BrS types were also observed in other left ventricular segments.
Conclusion. ECGi could noninvasively characterize ventricular activation in BrS patients with spontaneous and drug-induced type 1 pattern, revealing regional variations that may aid risk stratification.