Use of implantable loop recorders in patients with Brugada syndrome and suspected risk of ventricular arrhythmia.

AIMS: Implantable cardioverter defibrillator (ICD) therapy is recommended in patients with Brugada syndrome (BS) who experienced aborted sudden cardiac death (SCD) or syncope while the risk stratification of ventricular arrhythmias is a difficult step in patients with atypical symptoms. Implantable loop recorder (ILR) use has been proposed to study patients with unexplained recurrent syncopal events, but its usefulness remains to be defined in patients with BS. In this retrospective study we aimed to investigate the effectiveness of ILR as a diagnostic tool in BS patients suspected of low or moderate risk of SCD.

METHODS AND RESULTS: We gathered data from 11 ILR recipients with supposed risk of ventricular arrhythmia, issue of Amiens registry of 204 patients with BS. We reported clinical events before and after implant, electrocardiogram (ECG) characteristics, ILR findings, and its limitations as well as tried to specify ILR utility in diagnosis approach and its consequent contribution to guide the optimal therapy. Within the 11 patients (8 men, 3 women), 9 were symptomatic, and 5 had a spontaneous Type 1 ECG pattern. During mean follow-up period of 33 months, 8 patients had a recurrence of symptoms with a mean delay of 9 months after implant. Bradycardia (two atrioventricular blocks and two sinus bradycardia) was detected in four out of eight patients (50%), and there was no ventricular arrhythmia in any patient during symptomatic events which included six vasovagal syncopes and two epileptic seizures. Two initially asymptomatic patients did not experience any symptoms after ILR implant and their ILR recordings did not reveal any arrhythmias.

CONCLUSION: The ILR contributed to the exclusion of a ventricular arrhythmia as a mechanism of an atypical syncope in patients with electrocardiographic BS and the suspension of the ICD implant. Episodes of transient symptomatic bradycardia were the most common findings suggesting the vagal mechanism of symptoms. The use of ILR should be considered in selected patients with atypical syncope and spontaneous or transient Type 1 ECG pattern.