Mapping and Ablation of the Pulmonary Veins and Cavo-Tricuspid Isthmus With a Magnetic Resonance Imaging–Compatible Externally Irrigated Ablation Catheter and Integrated Electrophysiology System

Abstract

Background— Magnetic resonance imaging (MRI)–guided interventional electrophysiology (EP) has rapidly emerged as a promising alternative to x-ray–guided ablation. We aimed to evaluate an externally irrigated MRI-compatible ablation catheter and integrated EP pacing and recording system, testing the feasibility of pulmonary vein and cavo-tricuspid isthmus ablation. Methods and Results— Externally irrigated MRI-compatible ablation and diagnostic EP catheters and an integrated EP recording system (Imricor Medical Systems, Burnsville, MN) were tested in n=11 sheep in a 1.5-T MRI scanner. Power-controlled (40 W, 120-second duration) lesions were formed at the pulmonary vein and cavo-tricuspid isthmus. Real-time intracardiac electrograms were recorded during MRI. Steady-state free precession non–breath-hold images were repeatedly acquired to guide catheter navigation. Lesion visualization was performed using noncontrast (T2-weighted turbo spin echo pulse sequence) and gadolinium-diethylene triamine pentaacetic acid–enhanced T1-weighted imaging (inversion-recovery gradient echo pulse sequence). Catheters were able to be visualized and navigated under cardiovascular magnetic resonance guidance. In total, 8±2.5 lesions (radiofrequency time, 16±4.2 minutes) were formed at the pulmonary vein ostia, and 6.5±1.3 lesions (radiofrequency time, 13±2.2 minutes) were formed at the cavo-tricuspid isthmus, with the end point of bidirectional block. The mean procedure time was 150±55 minutes. Lesion visualization with both T2W imaging and contrast-enhanced imaging correlated with sites of injury at autopsy. Conclusions— These data demonstrate the feasibility of using multiple catheters, an integrated EP pacing and recording system, and externally irrigated ablation with cardiovascular magnetic resonance guidance to undertake clinically relevant biatrial mapping and ablation.

MR Imaging in Hypertrophic Cardiomyopathy: From Magnet to Bedside

“…Furthermore, LGE imaging enables the assessment of additional arrhythmic substrates and postablation lesions within the left atrium (115). Recently, ablation procedures in an MR environment have become feasible in the research setting, potentially opening the door for radiation-free procedures in HCM patients (116,117).…”

MR Imaging–guided Electrophysiological Ablation Studies in Humans with Passive Catheter Tracking: Initial Results

“…MR imaging-guided invasive diagnostic EP studies have been reported in animal studies and in a small series of five patients in which active and passive catheter-tracking techniques were used (12)(13)(14)(15)(16). We hypothesize that realtime MR imaging-guided radiofrequency ablation of atrial flutter is feasible in patients.…”

Interventional CMR: Clinical Applications and Future Directions

“…Using these systems, pre-clinical feasibility of electroanatomic mapping and ablation of the left ventricle [8], pulmonary veins and cavo-tricuspid isthmus [70, 71], and MR-guided cannulation of the coronary sinus [72] have been described. In recent years, electroanatomic mapping and ablation of atrial arrhythmias in humans have been reported [73–75], which represents an important milestone in the clinical translation of iCMR (Fig.…”