Electroanatomic Mapping and Radiofrequency Ablation of Porcine Left Atria and Atrioventricular Nodes Using Magnetic Resonance Catheter Tracking

Abstract

Background-The MRI-compatible electrophysiology system previously used for MR-guided left ventricular electroanatomic mapping was enhanced with improved MR tracking, an MR-compatible radiofrequency ablation system and higher-resolution imaging sequences to enable mapping, ablation, and ablation monitoring in smaller cardiac structures. MR-tracked navigation was performed to the left atrium (LA) and atrioventricular (AV) node, followed by LA electroanatomic mapping and radiofrequency ablation of the pulmonary veins (PVs) and AV node. Methods and Results-One ventricular ablation, 7 PV ablations, 3 LA mappings, and 3 AV node ablations were conducted.Three MRI-compatible devices (ablation/mapping catheter, torqueable sheath, stimulation/pacing catheter) were used, each with 4 to 5 tracking microcoils. Transseptal puncture was performed under x-ray, with all other procedural steps performed in the MRI. Preacquired MRI roadmaps served for real-time catheter navigation. Simultaneous tracking of 3 devices was performed at 13 frames per second. LA mapping and PV radiofrequency ablation were performed using tracked ablation catheters and sheaths. Ablation points were registered and verified after ablation using 3D myocardial delayed enhancement and postmortem gross tissue examination. Complete LA electroanatomic mapping was achieved in 3 of 3 pigs, Right inferior PV circumferential ablation was achieved in 3 of 7 pigs, with incomplete isolation caused by limited catheter deflection. During AV node ablation, ventricular pacing was performed, 3 devices were simultaneously tracked, and intracardiac ECGs were displayed. 3D myocardial delayed enhancement visualized node injury 2 minutes after ablation. AV node block succeeded in 2 of 3 pigs, with 1 temporary block. Conclusions-LA mapping, PV radiofrequency ablation, and AV node ablation were demonstrated under MRI guidance.Intraprocedural 3D myocardial delayed enhancement assessed lesion positional accuracy and dimensions. Key Words: catheter ablation Ⅲ MRI Ⅲ electrophysiology mapping T he current state-of-the-art electrophysiology (EP) practice for treatment of atrial fibrillation (AF) uses registration of preacquired CT or MRI of the atrium and pulmonary veins (PVs) with an electroanatomic monitoring (EAM) system to guide diagnostic catheterization and radiofrequency ablation (RFA). 1,2 Recent results suggest that MRI may also have utility after left atrial RFA in the assessment of ablation lesions 3,4 and may prove useful in determining circumferential ablation gaps that can contribute to the recurrence of AF. 5 Clinical Perspective on p 704The growing use of preinterventional and postinterventional imaging suggests that interventional MRI (I-MRI) may provide additional benefits. I-MRI may permit more precise EAM mapping because I-MRI provides up-to-date anatomic scans and does not require coregistration with a scan performed hours or days previously. 5 I-MRI also offers direct visualization of ablation injuries, through methods such as T2-weighted imaging and 3D myocardial...

Cardiac Electrophysiology Under MRI Guidance: an Emerging Technology

“…Figure 4). 35 They went on to investigate realtime visualisation of lesion formation, 48 a challenging area that has also been investigated by a group in Utah, USA. …”

“…Cardiac Electrophysiology Under MRI Guidance Diagnostic Electrophysiology & Ablation thickness, one slice per 2 second acquisition). 48 In the report, details regarding the results of imaging are limited to only presentation within a figure and were not quantified, but they appeared promising.…”

“…The susceptibility artefact of the MR-compatible catheters is generally small, facilitating such an approach; this would enable immediate reapplication of energy if the lesion were judged inadequate. 48,54 In the longer term, it is likely that real-time lesion formation imaging will rely on more novel sequences, and exploit acute physiological changes such as MR thermometry (see Figure 1). …”

A fully automatic deep learning method for atrial scarring segmentation from late gadolinium-enhanced MRI images

“…At present, electro-anatomical mapping (EAM) system, which is performed during the electrophysiological study, is considered to be a clinical reference standard technique for the assessment of the LA substrate and ablation-induced scarring. However, EAM is invasive and suffers from ionizing radiation and its suboptimal accuracy, which has reported errors of up to 10 mm in the localization of scar tissue [4]. Noninvasive late gadolinium-enhanced (LGE) MRI is an established method for visualizing and assessing myocardial infarction or fibrosis [5].…”

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

“…[3][4][5][6][7][8] Modern clinical EP procedures typically use multiple catheters, along with integrated pacing and recording systems, to diagnose and ablate cardiac arrhythmias. Furthermore, complex procedures, such as atrial fibrillation ablation, typically use externally irrigated catheters to achieve adequate lesion depth and improve safety profile.…”