Implantable loop recorders in children and adolescents with Brugada syndrome: the YoungBruLoop study

Abstract Background Young (<18 years of age) patients with Brugada syndrome (BrS) are often underrepresented in BrS studies and their management, especially related to syncopal episodes, remains unclear. Purpose To describe the arrhythmia prevalence and clinical implication derived from continuous rhythm monitoring by implantable loop recorder (ILR) among patients younger than 18 years of age, and to assess the etiology behind syncope of undetermined origin. Methods A total of 147 BrS patients with ILR were enrolled in 12 international centers and divided into pediatric (age <12 years; n=77, 52%) and adolescents (age 13 to 18 years; n=70, 48%). Results Mean age was 11.3 years (36.1% females, 21.1% spontaneous type I ECG). Forty-six patients (31.2%) underwent ILR implant due to syncope. Over a median follow-up of 3.6 years, an arrhythmic event was recorded in 22.4% of patients and in the vast majority of cases it was of non-ventricular origin (44% atrial, 47% bradyarrhythmias). Predictors of arrhythmias at univariate Cox Regression analysis were spontaneous type I ECG (HR 2.1 - 95%C.I. 1.1-4.1), history of syncope (HR 3.1 - 95%CI 1.5-6.3) and age >12 years (HR 2.0 - 95%C.I. 1.0-3.3). Ventricular arrhythmias occurred in 4 patients, all with spontaneous BrS, and were related to fever in half of cases. In patients with recurrent syncope, the prevalence of truly arrhythmic syncope was 17.8%, and it was due to brady-, atrial- and ventricular arrhythmias in 40%, 20% and 40% of cases, respectively. Conclusions Continuous rhythm monitoring with ILRs in BrS pediatric patients detects a broad range of heart rhythm disturbances including life-threatening arrhythmias. Ventricular arrhythmias occur predominantly in patients with spontaneous type I ECG and in half of cases are fever-related. Despite the young age, brady- and atrial arrhythmias are overall frequent and represent the cause of arrhythmic syncope in 60% of patients. Young BrS patients with syncope of undetermined origin may benefit from ILR implant.