Spontaneous type 1 electrocardiographic pattern is associated with cardiovascular magnetic resonance imaging changes in Brugada syndrome

Abstract

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. 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. 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. 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). 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.