192 Assessment of a relationship between functional and structural abnormalities in Brugada syndrome

Abstract

Although Brugada syndrome (BrS) is a primarily electrical disease leading to conduction slowing, it is now acknowledged that structural alterations of the myocardium are frequently associated. Those two factors, may result in both contraction heterogeneity and remodeling of the right ventricle (RV). Radionuclide angiocardiography (RNA) with phase analysis is able to quantify contraction delays and to evaluate volumes and systolic function of ventricles. The aim of this study was to assess both functional and structural alterations of the RV in patients with BS and to investigate a relationship between them. Multiharmonic Fourier phase analysis of planar RNA was used to quantify contraction heterogeneity, and gated bloodpool SPECT to assess ventricular volumes and function in 71 patients with proven BrS [classified according to their spontaneous ECG pattern recorded just prior to ERNA as: concealed (n=26), type 2/3 (n=28), type 1 (n=17)] and 18 controls. RV contraction heterogeneity was greater in patients with BrS compared to controls (17.2±0.4° vs 15.1±0.7° respectively, p=0.007), and increased according to the repolarisation pattern from concealed forms to type 1 (ANOVA p=0.02). The increase of RV contraction heterogeneity was associated with an increased apex to RVOT contraction delay (r=0.4, p=0.006). RV end-diastolic and end-systolic volumes were greater in patients with BrS compared to controls (156±6 vs 134±7 ml, and 88±4 vs 73±4 ml respectively, p=0.02), to a similar proportion so as the ejection fraction was not significantly impaired (44±1% vs 45±2% respectively, p=0.4). Finally, there was no relationship between the magnitude of contraction heterogeneity and RV remodeling. The left ventricle was free of abnormality. In patients with BrS, RV contraction heterogeneity increases with the magnitude of repolarisation abnormalities, contrary to RV remodeling which is present to a mild extent whatever the repolarisation pattern.