Ventricular conduction delay as marker of risk in Brugada Syndrome. Results from the analysis of clinical and electrocardiographic features of a large cohort of patients

Abstract

Background: Brugada Syndrome is a genetic arrhythmogenic disease with a variable clinical spectrum. The role of clinical and ECG parameters in the risk stratification is still uncertain.

Aims: In a large cohort of Brugada patients we analysed clinical and ECG features to determine the variables with prognostic value for the occurrence of a first documented arrhythmic event and for recurrences.

Methods: We enrolled 614 patients, subdivided into 3 groups according to their clinical presentation: 531 (88%) asymptomatic, 69 (10%) with previous unexplained syncope and 14 (2%) with aborted sudden death. We also compared the ECG characteristics of patients with a single documented arrhythmic event (either at presentation or at follow-up, 17 patients), with those of patients with arrhythmic recurrences (13 patients).

Results: The event rate was 1.3% in the asymptomatic patients and 15% among patients with unexplained syncope (median follow-up 6 years), p < 0.0001. In both groups a QRS duration ≥110 ms in lead II and/or V6 and/or S wave duration ≥40 ms in lead I and/or II were significant risk factors for the occurrence and timing of events at follow-up. The same ECG risk factors were also significantly associated with arrhythmic recurrences.

Conclusions: The arrhythmic risk of Brugada patients is related not only to the symptoms at presentation, but also to the presence of a ventricular conduction delay (QRS duration ≥ 110 ms and/or S wave duration ≥ 40 ms). The ECG conduction parameters also affect the timing of events and recurrences.

Keywords: Brugada Syndrome; Conduction delay; Electrocardiography; Sudden cardiac death; Unexplained syncope.