Electroanatomic Mapping of the Left Ventricle in a Porcine Model of Chronic Myocardial Infarction With Magnetic Resonance–Based Catheter Tracking

Abstract

Background-X-ray fluoroscopy constitutes the fundamental imaging modality for catheter visualization during interventional electrophysiology procedures. The minimal tissue discriminative capability of fluoroscopy is mitigated in part by the use of electroanatomic mapping systems and enhanced by the integration of preacquired 3-dimensional imaging of the heart with computed tomographic or magnetic resonance (MR) imaging. A more ideal paradigm might be to use intraprocedural MR imaging to directly image and guide catheter mapping procedures. Methods and Results-An MR imaging-based electroanatomic mapping system was designed to assess the feasibility of navigating catheters to the left ventricle in vivo using MR tracking of microcoils incorporated into the catheters, measuring intracardiac ventricular electrograms, and integrating this information with 3-dimensional MR angiography and myocardial delayed enhancement images to allow ventricular substrate mapping. In all animals (4 normal, and 10 chronically infarcted swine), after transseptal puncture under fluoroscopic guidance, catheters were successfully navigated to the left ventricle with MR tracking (13 to 15 frames per second) by both transseptal and retrograde aortic approaches. Electrogram artifacts related to the MR imaging gradient pulses were successfully removed with analog and digital signal processing. In all animals, it was possible to map the entire left ventricle and to project electrogram voltage amplitude maps to identify the scarred myocardium.

Cardiac Electrophysiology Under MRI Guidance: an Emerging Technology

“…As discussed, there are significant concerns regarding RF safety for long transmission lines, while they must remain capable of conducting μV heart volume at the beginning of the procedure, and then to display the location within a segmented chamber of the volume (see Figure 4). 28,34,35 Manual or automated chamber segmentations have both been employed to provide an interface that closely mimics the strengths of a clinical EAM system. Passive and active tracking sequences may be interleafed, providing real-time location updates with visualisation of device position and surrounding anatomy, and the passive imaging slice position can be coordinated with catheter tip position.…”

“…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. …”

Novel Imaging Approaches for Predicting Arrhythmic Risk

“…Inhomogeneous scarring with varying degrees of subendocardial myocardial fiber preservation within dense zones of fibrosis results in slowed conduction, nonuniform anisotropy, and the presence of conduction channels leading to re-entrant VT. 53,54 Having superb imaging quality with high temporal and spatial resolution in even the most challenging patients, CMR provides excellent visualization and characterization of substrate. The most useful technique is late Figure 6.…”

Feasibility of Contrast-Enhanced and Nonenhanced MRI for Intraprocedural and Postprocedural Lesion Visualization in Interventional Electrophysiology

“…First studies reported on feasibility of real-time MRI for catheter guidance in diagnostic electrophysiology studies 10 and electroanatomic mapping with magnetic resonance-based catheter tracking. 11 Just recently, even complex electrophysiological interventions such as AV modulation 12 and isthmus ablation 13 under magnetic resonance guidance have been performed using a magnetic resonance-conditional electrophysiology setup.…”