Epicardial electroanatomical mapping, radiofrequency ablation, and lesion imaging in the porcine left ventricle under real-time magnetic resonance imaging guidance-an in vivo feasibility study.

ABSTRACT: Aims:Magnetic resonance imaging (MRI) is the gold standard for defining myocardial substrate in 3D and can be used to guide ventricular tachycardia ablation. We describe the feasibility of using a prototype magnetic resonance-guided electrophysiology (MR-EP) system in a pre-clinical model to perform real-time MRI-guided epicardial mapping, ablation, and lesion imaging with active catheter tracking. Methods and results:Experiments were performed in vivo in pigs (n?=?6) using an MR-EP guidance system research prototype (Siemens Healthcare) with an irrigated ablation catheter (Vision-MR, Imricor) and a dedicated electrophysiology recording system (Advantage-MR, Imricor). Following epicardial access, local activation and voltage maps were acquired, and targeted radiofrequency (RF) ablation lesions were delivered. Ablation lesions were visualized in real time during RF delivery using MR-thermometry and dosimetry. Hyper-acute and acute assessment of ablation lesions was also performed using native T1 mapping and late-gadolinium enhancement (LGE), respectively. High-quality epicardial bipolar electrograms were recorded with a signal-to-noise ratio of greater than 10:1 for a signal of 1.5?mV. During epicardial ablation, localized temperature elevation could be visualized with a maximum temperature rise of 35?°C within 2?mm of the catheter tip relative to remote myocardium. Decreased native T1 times were observed (882?±?107?ms) in the lesion core 3-5?min after lesion delivery and relative location of lesions matched well to LGE. There was a good correlation between ablation lesion site on the iCMR platform and autopsy. Conclusion:The MR-EP system was able to successfully acquire epicardial voltage and activation maps in swine, deliver, and visualize ablation lesions, demonstrating feasibility for intraprocedural guidance and real-time assessment of ablation injury.

SUBMITTER: Mukherjee RK 

PROVIDER: S-EPMC6140436 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature