Development, Preclinical Validation, and Clinical Translation of a Cardiac Magnetic Resonance - Electrophysiology System With Active Catheter Tracking for Ablation of Cardiac Arrhythmia.

OBJECTIVES

This study sought to develop an actively tracked cardiac magnetic resonance-guided electrophysiology (CMR-EP) system and perform first-in-human clinical ablation procedures.

BACKGROUND

CMR-EP offers high-resolution anatomy, arrhythmia substrate, and ablation lesion visualization in the absence of ionizing radiation. Implementation of active tracking, where catheter position is continuously transmitted in a manner analogous to electroanatomic mapping (EAM), is crucial for CMR-EP to take the step from theoretical technology to practical clinical tool.

METHODS

The setup integrated a clinical 1.5-T scanner, an EP recording and ablation system, and a real-time image guidance platform with components undergoing ex vivo validation. The full system was assessed using a preclinical study (5 pigs), including mapping and ablation with histological validation. For the clinical study, 10 human subjects with typical atrial flutter (age 62 ± 15 years) underwent MR-guided cavotricuspid isthmus (CTI) ablation.

RESULTS

The components of the CMR-EP system were safe (magnetically induced torque, radiofrequency heating) and effective in the CMR environment (location precision). Targeted radiofrequency ablation was performed in all animals and 9 (90%) humans. Seven patients had CTI ablation completed using CMR guidance alone; 2 patients required completion under fluoroscopy, with 2 late flutter recurrences. Acute and chronic CMR imaging demonstrated efficacious lesion formation, verified with histology in animals. Anatomic shape of the CTI was an independent predictor of procedural success.

CONCLUSIONS

CMR-EP using active catheter tracking is safe and feasible. The CMR-EP setup provides an effective workflow and has the potential to change the way in which ablation procedures may be performed.