Value of programmed electrical stimulation in Brugada Syndrome: a cohort study

Abstract

Funding Acknowledgements Type of funding sources: None. Introduction Prognostic value of programmed electrical stimulation (PES) in Brugada Syndrome (BrS) remains controversial. Substantial controversy exists regarding usefulness of PES in identifying BrS patients at risk of sudden cardiac death (SCD). Implantation of an implantable cardioverter-defibrillator is the only reliable form of SCD prevention in this specific population Purpose To determine if induction of sustained ventricular arrhythmia (VA) in PES is a predictor of cardiac events (CE), defined as the composite of SCD, appropriate ICD therapy for VA or unexplained syncope. Methods A retrospective analysis of 34 patients with spontaneous or pharmacologically induced type 1 Brugada pattern, submitted to electrophysiology study with PES between 2015 and 2019 in a Portuguese Center, was performed. Patients were followed for 24 months. Hospital records and monitoring data from cardiac devices were consulted. The Mann-Whitney U test was used for median comparison between groups. Binary logistic regression through the stepwise method was performed to evaluate categorical features. Results 35% (n=12) and 27% (n=9) had spontaneous type 1 and type 2 Brugada pattern in basal electrocardiography, respectively. 23% (n=8) had VA induced by PES. The mean age was 51,2±12,3 years. 71% (n=24) were male. 15% (n=5) had history of cardiac syncope, and 27% (n=9) had a family history of SCD. 9% (n=3) were carriers of a SNC5A mutation. Mean AH time and HV time were, respectively, 105±31,9, and 49±8,5ms. During the 24 months of follow-up, 9% (n=3) suffered a CE (2 unexplained syncope and 1 SCD). None of the patients who suffered CE had VA inducible at PES study. There was no statistical significance in the occurrence of cardiac events when comparing both groups (VA induced in PES vs. no induced arrhythmia) (p=0,49, OR 0,89, IC 95% 0,70;1,02). Through binary logistics, adjusted for potential confounders (gender, history of syncope, history of family SCD and identification of a genetic variant), patients with spontaneous type 1 Brugada pattern in basal electrocardiography were 2,2 times more likely to have a CE (IC 95% 0,12;40,2). Conclusion In this population, VA induced by PES was not a predictor of CE during the follow-up period, which highlights the difficulty of risk stratification in patients with BrS. New risk-stratification tools are urgently needed to select those patients at higher-risk of SCD, which are candidates for prophylactic ICD implantation.