Midterm results of bipolar ablation in patients with intramural substrate and recurrent VTs based on a single center experience

Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation of VTs and intramyocardial substrate (IS) remains a challenge that may require alternative mapping and ablation strategies such as bipolar ablation (BA) to achieve VT non inducibility. However, the long-term success of these alternative strategies is still uncertain. Purpose The aim of this study was to report the midterm center experience success of BA RF ablation of VT in patients with documented intramyocardial scar in cardiac imaging. Methods 19 patients with documented intramyocardial substrate on cardiac imaging (cardiac MRI or cardio CT with delayed enhancement) and VT recurrences after at least one conventional catheter ablation were retrospectively included. The intraprocedural success (i.e. VT non inducibility at the end of procedure) respectively midterm success (i.e VT recurrence after 6 months from BA) were investigated. The ablation was performed using a special RF generator which permits bipolar RF ablation between 2 irrigated catheters. Results A total number of 19 patients were included (100 % men, mean age 66,7 ± 9,16 y/o). The mean LVEF was 39,5 ± 5,7. The distribution of underlying structural heart disease was as follow: 21 % ischemic cardiomyopathy (4 out of 19 patients), 52 % dilative cardiomyopathy (10 out of 19 patients) respectively 26 % other etiologies (5 out of 19 patients). A mean number of 2 ± 1 conventional VT ablation were previously performed. In almost all patients (94 %, 18 out of 19 patients) the clinical VT was induced before the BA (mean CL 342 ± 91ms). The BA was performed predominantly septal (84%, 16 out of 19 patients). In 3 patients an endo/epicardial BA was performed. No VT was inducible any more at the end of procedure in 15 patients (79 %). At a mean follow up of 1 ± 0,5 years no recurrence of clinical VT was noted but non-clinical VT recurrence was seen in 9 patients (47 %) exclusively in patients with septal substrate. Conclusion BA represents a good alternative strategy for CA in patients with IS and failed conventional VT ablation with good acute success but high VT recurrence rate in patients with septal IS.