Interventional cardiac magnetic resonance guided flutter ablation: technical evolution, procedural characteristics, and clinical outcomes
L H G Hopman, S Mahmoodi, M J B Kemme, R D Van Luijk, M Koster, J L Nelissen, M J W Gotte, C P AllaartAbstract
Introduction
Interventional Cardiac Magnetic Resonance (MR) (iCMR) has emerged as a promising non-radiation strategy for performing catheter ablation. Over the past decade, technical advances, including MR-compatible catheters, real-time catheter navigation strategies, and more recently the integration of an MR-compatible electrophysiology (EP) platform, have enabled the first clinical applications. Typical atrial flutter ablation has served as an initial benchmark procedure for establishing feasibility. However, data on procedural efficiency and clinical outcomes in larger patient cohorts remain sparse.
Methods
We retrospectively analyzed 35 consecutive patients who underwent iCMR-guided cavotricuspid isthmus (CTI) ablation using an MR-compatible ablation catheter between September 2022 and February 2025. All procedures were performed on a 1.5T MRI scanner using either active catheter imaging (ACI, n=15; Advantage MR) or active catheter tracking (ACT, n=20), the latter also incorporating a 3D navigation and EP platform (Figure 1). Technical performance, procedural characteristics, acute success, and arrhythmia recurrence were assessed.
Results
Mean patient age was 66 ± 7 years; 9% were women. Acute bidirectional CTI block was confirmed in 32 of 35 patients (91%). Two procedures were terminated prematurely; one patient had intermittent complete AV block during catheter manipulation, while another experienced pacing failure during sinus arrest post-conversion atrial flutter requiring pacing support. In the third patient, persistent conduction was observed despite extensive CTI ablation. Mean total procedural duration was 106.7 ± 41.8 minutes in ACI-guided cases and 131.7 ± 35.8 minutes in ACT-guided cases (p=0.07). Technical or procedural challenges were reported in 19 cases (54%), most commonly related to difficulties in coronary sinus catheter positioning in the ACI-group and issues with the MRI–EP system interaction in the ACT-group. During a median follow-up of 23.6 months (IQR: 11.0 – 28.7), recurrence of typical flutter occurred in 8 of 32 patients with initial confirmed CTI block (25%) (Figure 2).
Conclusion
This study outlines the iterative development and initial clinical use of a first-generation MR-compatible ablation catheter and EP navigation system. In this large single-center series of iCMR-guided ablations for typical atrial flutter, both ACI- and ACT-guided navigation were feasible and safe. The ACT approach reduced catheter manipulation challenges but initially introduced system-related issues now resolved in the commercial platform. This paves the way for clinical adoption, as iCMR-guided ablation demonstrates potential as an efficient and versatile approach for treating more complex arrhythmias.Study FlowchartStudy Outcomes