Characteristics of patients with Brugada Syndrome and monomorphic ventricular tachycardia.

Abstract

Background: Brugada Syndrome (BrS) is an arrhythmogenic disorder associated with sudden cardiac death primarily due to ventricular fibrillation (VF). Monomorphic ventricular tachycardias (MVT) are rarely reported, and little is known about their characteristics.

Objective: To evaluate the characteristics of BrS patients presenting with MVT compared to those with VF.

Methods: We performed a retrospective multicentre study of BrS patients who received an implanted defibrillator (ICD). Inclusion criteria were: 1) initiation of ventricular arrhythmia on ICD recordings, 2) absence of anti-arrhythmic drugs or prior ventricular ablation. Arrhythmic events were classified as MVT or polymorphic VT/VF (both referred VF) according to the guidelines. We analysed clinical data, characteristics related to arrhythmia initiation and electroanatomical substrate.

Results: Among 793 BrS patients with ICDs (44.2±17.7 years, 37.1% women), 54 met the inclusion criteria. ICD recordings showed a total of 47 VF episodes and 27 MVT episodes, overlapping in only one patient. MVT patients were older at first event (47.7±13.4 vs. 40.7±12.6 years, p=0.06), had higher QRS duration, more prevalence of syncope, and later recurrences after ICD implantation (median 51 vs. 20 months, p=0.018). Rapid rhythms (>100 bpm) were more frequent before MVT than VF (48.1% vs. 8.5%, p<0.001) with a lower incidence of ectopy (22.2% vs 61.7, p=0.001). Abnormal epicardial substrate was broader in MVT patients in baseline conditions (11.3 ± 5.5 cm² vs. 6.8 ± 3.2 cm², p=0.006).

Conclusion: VF/PVT and MVT in patients with Brugada Syndrome have distinct clinical presentations. MVT shows a later onset compared to VF/PVT, and is associated with broader substrate area.