Identification of High-Risk Syncope Related to Ventricular Fibrillation in Patients with Brugada Syndrome

Background:Syncope in patients with Brugada syndrome (BS) is usually associated with ventricular tachyarrhythmia. However, some episodes of syncope could be related to autonomic disorders. We investigated the characteristics of syncope to differentiate high-risk syncope episodes from low-risk events. Methods and Results: Eighty patients with type 1 ECG and syncope were divided into two groups: patients with prdoromes (Prodromal group, N=40) and without prodromes (Non-prodromal group, N=40). Ventricular fibrillation (VF) was documented at initial episodes in 17 patients. Only 3 patients experienced prodromes before the onset of VF and 14 patients did not have prodromes (P=0.0023). Twenty-seven patients in the Prodromal group and 6 patients in the Non-prodromal group were considered to have syncope related to autonomic dysfunction. Recurrent syncope due to VF was more frequent in the Non-prodromal group (N=9) than in the Prodromal group (N=2; P=0.023) during the follow-up period (50±48months). Multivariate logistic regression analysis indicated that blurred vision (Hazard ratio 0.092) and existence of f-QRS (Hazard ratio 2.99) were independently associated with the occurrence of VF. Conclusion: Syncope without prodromes, especially blurred vision, and existence of fragmented QRS are high-risk signs for occurrence of VF in patients with BS.