Background: Patients with Brugada syndrome (BrS) and a spontaneous type 1 ECG are considered to be at greater increased risk for sudden cardiac death than are patients with an abnormal ECG only after administration of sodium channel blockers and therefore represent a more severe phenotype. Thus, it can be hypothesized that in the presence of a more severe electrical phenotype, structural and functional changes are more likely expected because electrical changes can play a causal role in producing structural changes.
Objective: The purpose of this study was to investigate whether the different ECG manifestations in patients with BrS are associated with structural changes detected by cardiovascular magnetic resonance imaging.
Methods: Cardiovascular magnetic resonance imaging was performed on 69 consecutive patients with proven BrS and 30 healthy controls. Twenty-six patients had a spontaneous diagnostic type 1 BrS ECG; the remainder had a type 1 response to ajmaline provocation. Left and right ventricular volumes and dimensions were assessed and compared with respect to ECG pattern.
Results: The right ventricular outflow tract area was significantly enlarged in patients with a spontaneous type 1 ECG compared to patients with a nondiagnostic resting ECG or controls (11 cm(2), 9 cm(2), and 9 cm(2), respectively, P < .05). Patients with a spontaneous type 1 BrS ECG revealed significantly lower left ventricular ejection fraction than did patients with a nondiagnostic resting ECG and controls (56 ± 5 vs 59 ± 5 vs 60 ± 4, respectively, P < .05) and significantly lower right ventricular ejection fraction (54 ± 5 vs 59 ± 5, P = .001) as well as end-systolic volumes compared to controls (34 ± 9 mL/m(2) vs 28 ± 79 mL/m(2), P = .02).
Conclusion: Patients with a spontaneous type 1 BrS ECG reveal significantly functional and morphological alterations in both the left and right ventricles compared to patients with basal nondiagnostic ECG or controls.
Copyright © 2010. Published by Elsevier Inc.