Background: Brugada syndrome (BrS) is associated with an increased risk for severe ventricular arrhythmias and sudden cardiac death. Although labeled as a disease occurring in structurally normal hearts, functional alterations in some patients, mostly affecting the right ventricle (RV) and less often the left ventricle (LV), have been identified using new imaging techniques. Mechanical dispersion (MD) by speckle tracking imaging has been previously used to predict arrhythmic events in various cardiomyopathies.
Purpose: To evaluate if LV and RV global longitudinal strain (GLS) and MD by speckle tracking analysis differ between BrS patients and healthy matched controls.
Methods: We included 148 patients with BrS and 67 healthy controls. Patients with coronary heart disease were excluded. For each patient, speckle tracking analysis was performed in 16 LV and 6 RV segments. The time to peak myocardial strain in each segment was measured as the time from onset of the QRS complex on the ECG to maximum myocardial shortening. GLS was defined as the mean of the peak strain in the 16 LV segments and the 3 RV free wall segments. MD was defined as the standard deviation of the time to peak in respectively the 16 LV segments, the 6 RV segments and the 3 RV free wall segments.
Results: LV, RV and RV free wall MD were significantly higher in patients with BrS than in healthy controls [38 (±11) vs. 33 (±8) ms, P<0.001; 29 (±17) vs. 24 (±14) ms, P<0.05; 20 (±17) vs. 15 (±11) ms, P=0.004]. LV and RV GLS did not differ significantly between BrS patients and healthy controls [-18.7 (±2.3) vs. -19.0 (±1.9) %, P=0.39 and -25.9 (±5.2) vs. -25.8 (±3.5) %, P=0.90].
Conclusion: BrS patients had a higher MD than healthy controls, both in the LV and RV. Both LV and RV GLS were not significantly altered in BrS compared to healthy controls. Therefore, MD by speckle tracking might be a potential marker for the risk stratification of arrhythmic events in BrS.