24Acute and long-term outcomes for patients undergoing radiofrequency catheter ablation of scar-related ventricular tachycardia by robotic catheter navigation

Abstract

Introduction: Robotically-guided ablation offers theoretical advantages with greater catheter stability that can improve lesion depth. We performed a non-randomised comparison of patients undergoing ventricular tachycardia (VT) ablation either manually or using the Hansen robotic system. Methods: Consecutive patients with infarct-related scar underwent VT ablation using the Hansen system to assess feasibility, and were compared with patients undergoing manual VT ablation during the study period. All cases underwent a transeptal endocardial approach, using CARTO™ and irrigated catheter ablation guided by activation and entrainment manoeuvres if VT was sustained and tolerated, or substrate modification. The 6 month pre-ablation Implantable Cardioverter Defibrillator (ICD) therapy (Anti-tachycardia pacing (ATP) + shocks) was compared with the post ablation burden represented as a 6 monthly rate of each patient's total therapy burden during follow up ((6/follow-up duration (mths)) x total therapies post ablation)). Results: 25pts had VT ablations for infarct related scar during the study period. 13 pts had robotically guided ablation and 12 pts had manual ablation. Patients in both the robotic and manual groups had significantly impaired left ventricular function (EF 27±14% vs. 32 + /-11% respectively; p=0.32). The previous coronary revascularisationapproach, use of cardiac resynchronisation and amiodarone were similar in both groups. However 31% (4/13) of patients undergoing robotic ablation had been referred due to a failed manual approach and persisting high therapy burden as compared to 8% (1/12) redo procedures in the manual group (p=0.37). This was reflected by a trend towards higher pre-ablation therapy burden in the robotic as compared to the manual group (mean 312±566 vs. 11±9, p=0.08; median 11 vs. 9.5, p=0.50). In each group, 1 patient presented with slow incessant VT below the device therapy zone, and 1 patient had their device implanted post ablation. Post-procedure, the clinical VT was non-inducible in 85% (11/13) of the robotic group and in 92% (11/12) of the manual group. There were no peri-procedural complications. Mean follow-up was 23.5 months. Long-term mortality rates were similar (31%, 4/13 vs. 25%, 3/12; p=1.0). Post ablation, the 6 monthly therapy burden fell in both the robotic (mean reduction=290±560, median 3, p=0.047 Wilcoxon signed rank test) and manual (mean reduction=5.3±19, median 6.5, p=0.03) group. The overall reduction in therapy across all patients was 93% in the robotic and by 48% in the manual group. Conclusions: In this feasibility study, robotic VT ablation had a similar safety profile to manual ablation and a trend towards greater therapy reduction in a sicker cohort of patients. Table comparing acute procedural outcomes, 6 month pre/post ablation ICD therapies, and mortality rates between the robotic and manual groups. †Students t-test. §Fisher's exact test. ‖ Wilcoxon signed rank test. ![Graphic][1] [1]: /embed/inline-graphic-1.gif