Introduction: Catheter ablation of VTs and intramyocardial substrate (IS) remains challenging requiring alternative strategies such as bipolar ablation (BA) in order to achieve acute non inducibility. However, the long-term success of these alternative strategies is still uncertain. The aim of this study was to report the midterm success of bipolar RF ablation based on a single center experience.

Methods: Nineteen 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 irigated 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. A VT was still inducible at the end of procedure in 4 out 19 patients (21 %). At a mean follow up of 1 ± 0,5 years the VT recurrence rate 47 % (9 out 19 patients) exclusively in patients with septal substrate. No VT recurrence was reported in patients with other location of IS. 

Conclusion: BA represents a good alternative strategy for CA in patients with IS and failed conventional VT ablation with a decent acute success but still high VT recurrence rate in patients with septal IS.