Event rates and risk factors in patients with Brugada syndrome and no prior cardiac arrest: A cumulative analysis of the largest available studies distinguishing ICD-recorded fast ventricular arrhythmias and sudden death

Abstract

All available studies that have addressed the issue of risk stratification in patients with type 1 Brugada electrocardiographic (ECG) pattern have considered a combined end point constituted by implantable cardioverter-defibrillator-recorded fast ventricular arrhythmias (ICD-FVA) and sudden death (SD) in patients without ICD. As ICD-FVA are only a surrogate of SD, we tried to focus on the prognostic value of classical risk factors by separating patients with ICD-FVA from those without ICD who suffered SD. We made a cumulative analysis of the largest available studies. Studies were selected in which the incidence of FVA and SD could be determined in patients with and without ICD separately. In addition, we tried to analyze the prognostic value of risk factors in patients with and without ICD separately. A total of 2176 patients were recruited from 5 studies, about one-third of whom had an ICD and two-thirds did not. Event rates per 1000 patient-years of follow-up were 31.3 (25–39) and 6.5 (4-10) in patients with and without ICD, respectively (P < .001). When considering FVA in patients with ICD, each single risk factor (spontaneous type 1 ECG pattern, familial juvenile SD, and +EPS) displayed limited clinical value, mainly owing to its low specificity (21%-61%) and low positive predictive value (9%-15%). In patients with type 1 Brugada ECG pattern, most arrhythmic events occur in patients with an ICD while SD is rare in patients without an ICD. While we have an acceptable ability to predict ICD-FVA, we have insufficient data to predict SD.