The prognostic value of programmed electrical stimulation (PES) in Brugada syndrome (BrS) remains controversial. One of the reasons for discrepant results may be due to the selection of stimulation protocol. Objective: To evaluate the prognostic value of a positive PES result (PES+) according to the inducible pacing sites and the number of extrastimuli in BrS patients without previous cardiac arrest (CA). Methods: We enrolled 224 consecutive BrS patients without previous CA (mean age 51±14

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... , 209 males), who underwent PES with the identical protocol. Clinical outcomes of development of CA were explored in the patients with and without PES+ according to sites and number of extrastimuli. Results: During a mean follow-up period of 76 months, 12 cardiac events (CE: sudden cardiac death or documented VF) occurred (8 with and 4 without PES+). The incidence of CE was not different in patients with and without PES+, those with PES+ from RVA (n=72) or RVOT (n=60), and those with and without PES+ by up to 2 extra-stimuli (n=58). However, in patients that were PES+ by single extrastimulus (n=8) the incidence of CE was significantly higher than in patients without PES+ (8.8 vs 0.6%/yr, p<0.0001). On univariate analysis, syncope, spontaneous type 1 ECG, and PES+ by a single extra-stimulus were associated with CE. Conclusions: Details of the stimulation protocol may be important for risk assessment in BrS patients without previous CA. A single extra-stimulus may be useful to distinguish intermediate-from low-risk BrS patients, regardless of choice of sites. Introduction: Catheter ablation of ventricular arrhythmia has been greatly facilitated by 3D image integration from MRI or CT. A novel quality of image information is been applied here that adds a detailed distribution of the sympathetic activity, in addition to the scar information (by perfusion imaging from SPECT). Both datasets are projected onto the 3D endo-and epicardial surface of the left (LV) and right ventricle (RV) aquired from contrast computed tomography (cCT). Methods: A total of 10 patients (6 male, median age 42.8 yrs) underwent dual tracer nuclear imaging with iodine-123 metaiodobenzylguanidine (mIBG, for sympathetic innervation) and technetium-99m (Tc-99m) methoxyisobutylisonitrile (MIBI, for perfusion) using a dedicated cardiac camera (D-SPECT). Three patients had arrhythmogenic right ventricular cardiomyopathy (ARVC), two had dilated cardiomyopathy (DCM), one had sarcoidosis, one had ischemic cardiomyopathy (ICM), one had tetralogy of Fallot, one had catecholaminergic polymorphic ventricular tachycardia (CPVT) and one had Takotsubo syndrome. All patients also underwent cardiac cCT. Results: In all patients, both the dual tracer studies and CT scans were performed without any complications. Subsequently, the acquired nuclear information was merged with the 3D cCT and the resulting merged images were imported into the 3D electro anatomical mapping system (CARTO). By superimposition of both mIBG and MIBI meshes, a region of mismatch (ROM) was defined which was located around the perfusion defect in all cases and exceeded the size of the perfusion defect. Good correlation was demonstrated comparing voltage amplitude map (VAM) to perfusion maps, except in areas inaccessible to sequential mapping. Conclusion: The combination of dual tracer nuclear imaging using mIBG and MIBI information with 3D cCT is feasible and provides a novel type of "road map" for catheter ablation procedures in patients with ventricular arrhythmia. Superimposition allows for the first time to localize the region of mismatch which may prove during invasive EP study to be a marker of pro-arrhythmogenicity.