Preprocedural substrate assessment with computed tomography as an adjunct to endocardial voltage mapping for ablation of ventricular tachycardia: feasibility, procedural data and outcomes
Authors: Schipper J , Kalbaum J J , Woermann J , Filipovic K , Dittrich S , Scheurlen C , Erlhoefer S , Pavel F , Sultan A , Lueker J , Steven D , Van Den Bruck J 
Published: May 2024

Abstract

Background
Catheter ablation is an established therapy for ventricular tachycardia (VT) with endocardial voltage map (EVM) being the standard tool to characterize proarrhythmic substrate. However, this method is limited in certain ways, especially as intramural or epicardial substrate is not detected. In this context, multi-detector computed tomography (MDCT) has emerged as a promising alternative to cardiac MRI for preprocedural substrate assessment.

Purpose
Data regarding MDCT- guided VT ablation is scarce, especially in the context of late iodine enhancement MDCT. Present study sought to assess procedural parameters, safety, and efficacy of MDCT-guided VT ablation in direct comparison with a conventional VT ablation approach and is, to the best of our knowledge, the first systematic evaluation of clinical routine use of MDCT for preprocedural substrate assessment.

Methods
All patients (pts) undergoing VT ablation between January 2022 and August 2023 were included in this single-center registry. For MDCT-guided VT the CT images were uploaded to an online platform and processed using a dedicated software. Procedural parameters of MDCT-guided procedures were compared with the conventional EVM approach, and the study endpoint was a composite of death from any cause, heart failure hospitalization, and recurrence of VT.

Results
A total of 70 consecutive pts (age 62±13 y, 83% male) was included, of those 27/70 pts (39%) undergoing MDCT-guided and 43/70 pts (61 %) conventional VT ablation. An additional EVM was acquired in all MDCT pts. Baseline characteristics were similar. At comparable procedure durations (MDCT: 217±74 min, EVM: 194±57 min, p=0.15) the MDCT group showed a trend towards shorter mapping times (MDCT: 42±18 min, EVM: 49±13 min, p=0.09), particularly in cases with non-ischemic cardiomyopathy (NICM) (MDCT: 41±20 min, EVM: 54±15 min, p=0.07). An epicardial access was obtained in 8/23 pts (30 %) in the MDCT group and in 6/47 pts (14 %) in the EVM group (p=0.13). Bipolar ablation due to intramural scar detected by MDCT was performed in 3/27 pts (11 %) and in none in the EVM group. There was no difference in manifestation of acute kidney injury (MDCT: 3/17 pts (18 %) vs. EVM: 4/24 pts (21 %), p=1.0). After a median follow-up of 116 days (IQR 80-260 days), the study endpoint occurred in 8/17 (47 %) pts after MDCT-guided and in 14/31 pts (45 %) after conventional VT ablation. In one patient in the MDCT group a relevant coronary artery stenosis with urgent revascularization occurred immediately after bipolar ablation at the LV summit. No other complications were observed.

Conclusion
MDCT-guided VT ablation is safe and feasible with no differences in contrast agent-induced kidney injuries. Preprocedural CT substrate assessment identified complex intramural and epicardial scar, leading to bipolar and epicardial ablation. Mapping times trended shorter in the MDCT group, particularly in non-ischemic cardiomyopathy cases.