Background-Whether Brugada syndrome (BrS) depends on functional epicardial substrates, which may be definitively eliminated by radiofrequency ablation, remains unknown. Methods and Results-Patients with BrS underwent epicardial mapping to identify areas of abnormal electrograms as target for radiofrequency ablation. Substrate identification consisted in mapping right ventricle epicardial surface before and after flecainide (2 mg/kg per 10 minutes). After radiofrequency ablation, flecainide and remap confirmed elimination of abnormal substrate, BrS ECG pattern, and ventricular tachycardia/ventricular fibrillation inducibility. Flecainide testing was performed at each follow-up visits ≤6 months. Fourteen patients with BrS, median age 39 years (30.3-42.3) with implantable cardioverter-defibrillator were enrolled. Low-voltage areas (<1.5 mV) were commonly identified on the anterior right free wall and right ventricular outflow tract, which increased after flecainide from 17.6 cm 2 (12.1-24.2) to 28.5 cm 2 (21.6-30.2; P=0.001). Similarly, areas with abnormal electrograms increased after flecainide from 19.0 (17.5-23.6) to 27.3 cm 2 (24.0-31.2; P=0.001). After 23.8 minutes (18.1-28.5) of radiofrequency ablation, abnormal electrograms disappeared, whereas low-voltage areas were replaced by scar areas (<0.5 mV) of 25.9 cm 2 (19.6-31.0). Substrate elimination resulted in BrS ECG pattern disappearance and no ventricular tachycardia/ventricular fibrillation inducibility without complications. After a median follow-up of 5 months (3.8-5.3), ECG remained normal despite flecainide. experimental observations suggested that RFA applied to the epicardium may be more effective than applied to the endocardium in eliminating VT in patients with BrS. 7 A more recent report from 9 symptomatic BrS patients with repetitive ICD shocks indicates that the electrophysiological substrate for the BrS is delayed depolarization exclusively over the anterior aspect of the RVOT epicardium and that catheter ablation of this abnormal area may prevent VT/VF. 8 These observations open the possibility that eliminating localized epicardial substrates responsible for the disease phenotype may cure patients with BrS. However, it is not known if there is a relationship between the presence, location and extent of the epicardial substrate abnormalities, and typical BrS ECG pattern. In addition, many other issues such as methodology for substrate identification and elimination and testing of acute and midterm results remain to be clarified. The purpose of this study was to systematically report the methodology, results, and complications of epicardial RFA of consecutive selected patients with BrS. Particular attention was focused on endocardial/epicardial mapping and flecainide testing to characterize and establish the most appropriate target sites for successful RFA and elimination of both ECG BrS pattern and inducibility of VT/VF. Conclusions-In patients with BrS Methods Patient CharacteristicsPatients referred to the Arrhythmology Departments of Maria ...

URL: https://clinicaltrials.gov. Unique identifier: NCT02641431.

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