Contraction alterations in Brugada syndrome; association with life-threatening ventricular arrhythmias

BACKGROUND: Brugada syndrome (BrS) is characterized by a high risk of sudden cardiac death. The clinical value of deformation imaging in patients with BrS is unknown. We aimed to assess whether echocardiographic speckle tracking parameters differ between: 1) BrS patients and healthy controls, 2) BrS patients with and without life-threatening ventricular arrhythmias.

METHODS: Left ventricle (LV) and right ventricle (RV) longitudinal strain and mechanical dispersion (MD) were derived from echocardiography at inclusion. Clinical and ECG data were retrospectively assessed. A life-threatening ventricular arrhythmia was defined as an aborted cardiac arrest or sustained ventricular tachyarrhythmia.

RESULTS: We included 175 BrS patients and 82 controls. LV and RV longitudinal strain were lower (-18.1 ± 2.6% vs. -18.8 ± 2.0%, p = 0.01 and - 24.4 ± 5.4% vs. 25.6 ± 3.7%, p = 0.04), while MD was higher [38 ± 11 ms vs. 33 ± 8 ms, p = 0.001 and 15 (8-25) ms vs. 11 (6-19) ms, p = 0.03] in BrS patients compared to controls. BrS patients who experienced a life-threatening ventricular arrhythmia (n = 19) had higher LV MD compared to those without events (43 ± 11 ms vs. 37 ± 11 ms, p = 0.02). An LV MD ≥40 ms was optimally associated with life-threatening ventricular arrhythmias [odds ratio 4.62 (95%CI 1.58-13.50), p = 0.005].

CONCLUSIONS: BrS patients had lower longitudinal strain and more heterogeneous contractions than healthy controls. Furthermore, BrS patients with a history of life-threatening ventricular arrhythmia had more heterogeneous LV contractions than those without. Therefore, LV MD may be a risk marker in BrS and its evaluation in prospective studies is needed.