Risk factors for cardiac events in patients with Brugada syndrome

INTRODUCTION Inconsistent results have been reported about the risk stratification of patients with Brugada syndrome. We have summarized the evidence regarding the strength of association between 6 risk factors (family history of sudden cardiac death [SCD] or syncope, inducible ventricular arrhythmias on electrophysiology study [EPS], spontaneous type 1 Brugada electrocardiogram [ECG], male sex, family history of SCD, and sodium voltage-gated channel alpha subunit 5 [SCN5A] gene mutation) and subsequent cardiac events in Brugada syndrome patients. METHODS Pubmed, Ovid, Embase, and the Cochrane Library were searched for studies published between January 1992 and March 2016. Only prospective studies (27 studies, 4494 patients) that reported estimates with 95% confidence intervals (CIs) of cardiac events for the 6 risk factors were included. RESULTS Family history of SCD or syncope (risk ratio [RR] 4.97, 95% CI 3.96-6.23, P < 0.001), inducible ventricular arrhythmia on EPS (RR 3.56, 95% CI 1.30-9.74, P = 0.01), and spontaneous type 1 Brugada ECG (RR 4.07, 95% CI 2.23-7.41, P < 0.001) were associated with an increased risk of future cardiac events. Spontaneous type 1 Brugada ECG was associated with an elevated risk of future cardiac events in patients without a family history of SCD. CONCLUSIONS Inducible ventricular arrhythmias on EPS, spontaneous type 1 Brugada ECG, and family history of SCD or syncope indicate a high risk of future cardiac events in patients with Brugada syndrome. Spontaneous type 1 Brugada ECG significantly increased the risk of future cardiac events in patients without family history of SCD.