Cardiac Magnetic Resonance-Guided Ventricular Tachycardia Substrate Ablation

Abstract

Objectives: This study assessed the feasibility and potential benefit of performing ventricular tachycardia (VT) substrate ablation procedures guided by cardiac magnetic resonance (CMR)-derived pixel signal intensity (PSI) maps.

Background: CMR-aided VT ablation using PSI maps from late gadolinium enhancement-CMR (LGE-CMR), together with electroanatomical map (EAM) information, has been shown to improve outcomes of VT substrate ablation.

Methods: Eighty-four patients with scar-dependent monomorphic VT who underwent substrate ablation were included in the study. In the last 28 (33%) consecutive patients, the procedure was guided by CMR. Procedural data, as well as acute and follow-up outcomes, were compared between patients who underwent guided CMR and 2 control groups: 1) patients who had PSI maps were available but the EAM was acquired and used to select the ablation targets (CMR aided); and 2) patients with no CMR-derived PSI maps available (no CMR).

Results: Mean procedure duration was lower in CMR-guided substrate ablation compared with CMR-aided and no CMR (107 ± 59 min vs. 203 ± 68 min and 227 ± 52 min; p < 0.001 for both comparisons). CMR-guided ablation required less fluoroscopy time than CMR-aided ablation and no CMR (10 ± 4 min vs. 23 ± 11 min and 20 ± 9 min, respectively; p < 0.001 for both comparisons) and less radiofrequency time (15 ± 8 min vs. 20 ± 15 min and 26 ± 10 min; p = 0.16 and p < 0.001, respectively). After substrate ablation, VT inducibility was lower in CMR-guided ablation compared with CMR-aided ablation and no CMR (18% vs. 32% and 46%; p = 0.35 and p = 0.04, respectively), without significant differences in complications. After 12 months, VT recurrence was lower in those who underwent CMR-guided ablation compared with no CMR (log-rank: 0.019), with no differences with CMR-aided ablation.

Conclusions: CMR-guided VT ablation is feasible and safe, significantly reduces the procedural, fluoroscopy, and radiofrequency times, and is associated with a higher noninducibility rate and lower VT recurrence after substrate ablation.

Keywords: cardiac magnetic resonance; conducting channels; image-guided ablation; substrate ablation.