New Onset of Ventricular Fibrillation Episodes in Asymptomatic Patients with Brugada Syndrome—Are Patients with Class IIb Safe?—

Abstract

Introduction: Japanese guideline of the Brugada syndrome (BS) defined the indication of the implantable cardioverter defibrillater (ICD) in asymptomatic patients with BS as patients having both family history of sudden death (FH) and induced ventricular fibrillation (VF) by programmed electrical stimulation (PES) (class IIa). When patients had one of these criteria, ICD indication considered as class IIb. We analyzed new onset of VF episodes in asymptomatic patients. Methods and Results: We analyzed 99 asymptomatic patients with Brugada type ECG. Fourty-seven patients had FH. VF was induced by PES in 44 patients. Criteria of ICD indication of class IIa, IIb, and III were met in 20, 50, and 29 patients, respectively. Three patients experienced new-onset VF episode during follow-up periods (84±43 months). Although there was no new-onset VF in patients with class IIa, all patients who experienced VF episodes belonged to class IIb (6%). All patients with new-VF had spontaneous type 1 ECG, induced VF by PES, positive late potential and fragmented QRS, but did not have FH and SCN5A mutation. Conclusion: Prediction of prognosis in patients with BS-ECG based on BS-guideline has limited value and occurrence of VF is not rare in patients with class IIb of ICD indication.