Interventional cardiac magnetic resonance-guided flutter ablation: Technical evolution and procedural insights from early clinical use.

BACKGROUND

Interventional cardiac magnetic resonance imaging (iCMR) enables catheter ablation without ionizing radiation and provides real-time soft-tissue visualization. Recent developments have enabled initial clinical applications, with typical atrial flutter ablation serving as a benchmark to evaluate feasibility.

OBJECTIVE

Describe procedural feasibility, efficiency, and clinical outcomes of iCMR-guided cavotricuspid isthmus (CTI) ablation in a single-center cohort.

METHODS

We retrospectively analyzed 35 consecutive patients who underwent real-time iCMR-guided CTI ablation between September 2022 and February 2025. Procedures were performed on a 1.5T MR imaging scanner using active catheter imaging (ACI, n = 15) or active catheter tracking (ACT, n = 20). Procedural characteristics, technical performance, acute success, complications, and 1-year arrhythmia recurrence were evaluated.

RESULTS

Mean age was 66 ± 7 years, and 9% were women. Acute bidirectional CTI block could be confirmed in 32 of 35 patients (91%). Median (interquartile range [IQR]) procedure duration was 106 (IQR, 70-128) minutes with ACI and 133 (IQR, 94-161) minutes with ACT (P = .07). Procedural or technical challenges occurred in 19 patients (54%), most commonly related to coronary sinus catheter positioning and workflow or system-integration issues. No major complications occurred. During 1-year follow-up, typical atrial flutter recurred in 6 of 32 patients (19%) with confirmed CTI block, with no difference between ACI (4 of 15 patients) and ACT (2 of 17 patients) (log-rank P = .29).

CONCLUSION

iCMR-guided CTI ablation was feasible and could be performed safely using both ACI and ACT. However, procedural complexity, prolonged procedure times, and recurrence rates reflect the early implementation phase of this first-generation iCMR platform. Ongoing advances in catheter technology, system integration, and workflow optimization are expected to further improve procedural performance and support broader clinical adoption.