Additional features in Brugada Syndrome stratification: frequent PVC and QRS duration

Abstract

Funding Acknowledgements Type of funding sources: None. Introduction Brugada syndrome (BrS) is a channelopathy with high prevalence of malignant arrhythmic events. The risk stratification in patients (pts) with Brugada electrocardiographic (ECG) pattern is of major importance, to prevent sudden cardiac death (SCD). A higher risk is evidenced in spontaneous type 1 pattern when compared with induced type-1 pattern, as so other electrocardiographic features have been explored aiming to detect additional prognostic factors. Purpose To evaluate the association of QRS duration and frequent premature ventricular contractions (PVC) with malignant arrhythmic events. Methods Prospective single-center study of consecutive pts with BrS, with spontaneous or induced type 1 pattern included from 2003 to 2021. All pts were enrolled in a protocol including annual non-invasive assessment with ECG and 24-hours Holter monitoring. Primary endpoints were defined as SCD or appropriate shocks in the context of ventricular tachycardia or fibrillation (VT/FV) during follow-up. Cox regression and Kaplan-Meier survival analyses were used to determine the association between the baseline ECG and Holter characteristics and the long-term risk of arrhythmic events. Results A total of 117 pts was included, 75 (65%) with a spontaneous type 1 pattern and 44 (33%) with an induced type 1 pattern. The mean age was 47±13years and 38 (32.5%) were male. During a median follow-up of 4.1±0.3 years, the primary endpoint occurred in 8 (6.8%) pts, with sudden cardiac death in 3 (2.6%) and appropriate shocks due to VT/FV in 5 (4.3%). Pts who suffered arrhythmic events had presented at the study inclusion higher QRS duration (124±18 vs. 108±16ms, p= 0.014) and more frequent PVCs on 24-hour Holter (169±297 vs. 29±198; p = 0.001) - Figure 1. Indeed, the presence of QRS ≥119ms was associated with a 7-fold higher risk (HR: 7.250, 95% CI 1.619-32.461, p = 0.010) and the presence of more than 6 PVC on 24-hour Holter was also associated with a 5-fold higher risk of malignant arrhythmic events (HR 5.376, 95% 1.186-24.260, p = 0.029). Conclusion QRS duration and frequent PVC may established themselves as additional risk factors. In our cohort, they were both predictors of arrhythmic events during follow-up and thus can further complement BrS risk stratification.

SCN5A mutation is associated with a higher Shanghai Score in patients with type 1 Brugada ECG pattern

“…Prolonged QRS has been associated with a higher incidence of symptoms and ventricular arrhythmias. [24][25][26] BrS often shows complex inheritance with incomplete penetrance and variable expressivity. 27 Data from the literature have suggested that the presence of SNPs might influence the clinical expression of SCN5A pathogenic mutations.…”

“…Prolonged QRS interval has been attributed to sodium current dysfunction mainly in the conduction system and specifically in the His-Purkinje system. Prolonged QRS has been associated with a higher incidence of symptoms and ventricular arrhythmias 24–26 …”