Safety and feasibility of multi-spline multielectrode mapping during ventricular tachycardia ablation in post-myocardial infarction patients

Abstract Background Multielectrode- and multi-spline catheters are increasingly used for mapping of post-myocardial infarction (MI) ventricular tachycardia (VT) and may allow for higher mapping efficiency and density. A potential proarrhythmic effect of these catheters has been suggested but not systematically studied. This is relevant as electrocardioversions (ECV) to terminate mechanically induced VTs are painful, can lead to map shift and can cause hemodynamic instability. Purpose The aims of this study are to compare mapping time for multi-spline- and single tip catheters, and to determine their arrhythmogenic effect during functional substrate mapping. Methods Consecutive post-MI patients undergoing VT ablation between 2021 and 2024 who provided informed consent for the study protocol were included. In all patients two separate functional substrate maps were created in a random order with a multi-spline catheter (Octaray or Pentaray) and the single-tip QDOT catheter. Mapping times and number of mechanically induced VTs were noted. Per protocol, mapping with the catheter under examination was prematurely terminated if two distinct, mechanically induced VT episodes requiring electric cardioversion (ECV) occurred followed by a new map with the second catheter. Results Twenty-eight patients (mean age 68±8 years, 96% male, median LVEF 39% [IQR 31 – 47] were included. Total substrate mapping time was 81 minutes [IQR 71 – 95]; 61 minutes [IQR 49 – 71] for the Q-dot and 24 minutes [IQR 18 – 31] for multi-spline catheters. In 15/28 patients the Q-dot was used to create the first map. Mean total procedural time was 300±55 minutes. Seventeen patients (61%) had at least one mechanically induced VT during the procedure (mean 2.2±3.2 VTs per patient). The mean number of mechanically induced VTs was higher with the multi-spline catheters compared to the single tip (mean induced VT 1.4±2.5 versus 0.8±1.5, p<0.05). In 18 patients mapping with the two catheters could be completed. In 10/28 patients 2 VT episodes that required ECV led to premature protocol termination, which was during mapping with the multi-spline catheters in 9/10. Conclusion Functional post-MI substrate mapping with multi-spline catheters is fast but hampered by mechanically induced VTs requiring recurrent cardioversion in 36% of patients. Usage of these catheters requires a careful risk-benefit assessment.Baseline characteristics Procedural data