Figure 1 illustrates the flowchart for a literature search and study selection. At the initial systematic searching, 330 potentially relevant articles were identified. After exclusion of 26 duplicate articles, 304 articles underwent title and abstract screening. Of these, 234 articles were excluded at this stage since they did not meet the inclusion criteria described above. Another two articles were excluded since they were written in non-English language. Sixty-eight articles underwent full-text review. Four articles were excluded, as they were derived from the same database that had been used for another manuscript which had already been included in the analysis. Another eight articles were excluded because of unclear description of the ablation strategy. As a result, a total of 56 articles with 388 patients (15 case series [3, 5,6,7,8,9,10,11,12,13,14,15,16,17,18] and 41 case studies [19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59]) were included. Systematic review was performed for descriptive outcomes in all 56 studies and single arm meta-analysis was performed for procedural outcomes of ablation procedures in 15 case series.

PRISMA (Preferred reporting items for systematic reviews and meta-analyses) flow chart for literature search and study selection

Patient characteristics in all 56 studies with 388 patients are described in Table 1. The majority of patients were male (87%), with a median age of 39 (IQR 34–50) years. Left ventricular (LV) function was reported in 264 patients (68%), all with preserved function. Right ventricular (RV) function was reported on echocardiogram in 241 (62%) patients. In one patient (0.3%), arrhythmogenic right ventricular cardiomyopathy (ARVC) was suspected on echocardiography, however it was unable to be confirmed due to inability to perform a magnetic resonance imaging (MRI) due to the presence of a non-MRI compatible ICD [6]. Cardiac MRI was reported in 158 (41%).

The patients’ initial presentations were described in 342/388 cases (88%). Among these 342 patients, 123 patients (36%) presenting following resuscitated cardiac arrest, 72 patients (21%) presenting following syncope and 147 patients (43%) presenting with other symptoms including palpitations, atrial arrhythmias and nocturnal agonal respiration.

ICD had been implanted prior to, or at the time of ablation, in 374/386 patients (97%), with 12/386 patients (3%) having declined ICD insertion, and the ICD status of the remaining two cases was not known [15]. Genetic testing for an SCN5A mutation was performed in 257 patients (66%), with 68 patients (26%) testing positive. Subsequent to initial diagnosis, presence of sustained VA prior to ablation procedure was described in 250 patients, of which 197 patients (79%) had documented spontaneous sustained VA, which included VF in 95/197 (48%), sustained monomorphic VT in 25/197 (13%), both rhythms (VT and VF) in 6/197 (3%) and unspecified sustained VA in 71/197 (36%). Forty-seven patients (19%) had not documented spontaneous sustained VA but induced VA before ablation procedure. Notably, six patients (2%) had not had any documented spontaneous or inducible VA prior to their ablation procedure [12, 20, 23, 54]. A total of 43/91 patients (47%) had previously documented VF storm.

The ablation strategy and approach in all 56 studies with 388 patients are summarized in Fig. 2. A variety of mapping was used. These included targeting of abnormal EGMs (defined as a combination of low voltage, late potentials or fractionated potentials) in 338 cases (87%), and targeting foci of PVCs or monomorphic VT in 47 cases (12%; PVC 38 cases, monomorphic VT 9 cases). An approach of combining targeting of abnormal EGMs and targeting PVC/VT was performed in three cases (1%).

Ablation strategy and approach in patients with Brugada syndrome. Endo endocardium, Epi epicardium, PVC premature ventricular complex, VT ventricular tachycardia

Following baseline electroanatomic mapping, pharmacological provocation was used to augment the arrhythmogenic substrate in 316/388 cases (81%). The provocation strategy was described in Table 2. The most frequently used strategy was sodium channel blocker in 309/316 cases (98%). Of these, ajmaline was the most frequently used in 235/309 cases (76%), following by pilsicainide in 36/309 cases (12%), flecainide in 20/309 cases (6%), propafenone in 10/309 cases (3%), and procainamide in 8/309 cases (3%). In nine cases, warmed 0.9% saline (39–40℃) was infused into the epicardial space [14, 55, 57, 58]. Two patients received both sodium channel blocker and epicardial warm water instillation [57, 58].

Subsequent to pharmacological or thermal provocation, substrate mapping was performed. A summary of the location of arrhythmogenic substrate is described in Fig. 3. A total of 330 patients underwent epicardial mapping including four patients who were ablated from the endocardium alone. In the majority of cases, abnormal substrate localized to the epicardial RVOT, however, extension of the abnormal substrate was highly variable, particularly after provocation. Detailed substrate localization was not available in 149 epicardial cases [5, 9]. Of the remaining 181 cases where epicardial ablation was performed, all cases involved epicardial RVOT (100%) [3, 7, 8, 12,13,14, 16,17,18, 20,21,22,23,24,25,26,27,28,29,30,31,32, 48, 50, 51, 54,55,56,57,58,59], with extension to the RV free wall in 10 cases (6%) [7,