Abstract Body (Do not enter title and authors here): Background
With the advent of stereotactic radioablation for cardiac arrhythmias, accurate non-contact mapping tools are increasingly important. Magnetocardiography (MCG) is promising but historically limited by supercooled sensors, extensive shielding, and long recording durations.
A novel magnetic sensor system developed by TDK Corporation may overcome these prior limitations, but rigorous validation against established methods has not been performed. Specifically, no prior study has directly validated this novel MCG system through a three-way comparison with electrocardiographic imaging (ECGi) and a gold-standard pacing location for atrial arrhythmia localization.
Hypothesis
We hypothesized that the novel MCG sensor system would perform comparably to ECGi in accurately localizing atrial activation origins, enabling the creation of reliable atrial activation maps.
Methods
Six swine (42.2 ± 5.3 kg) underwent placement of pacing wires in the right atrium to simulate focal atrial arrhythmias. Anatomical MRI scans precisely defined the gold-standard pacing lead position (Fig. A) and ECG electrode locations via fiducials. Atrium anatomy was segmented from MRI images and smoothed to create accurate anatomical models. Simultaneous MCG and ECGi signals were recorded during controlled atrial pacing. Latency maps were generated from denoised, beat-averaged signals (Fig. B). Localization accuracy between MCG and ECGi was compared using a paired Wilcoxon signed-rank test.
Results
Approximately 1000 P-waves per animal were analyzed. Median absolute localization error was 24.1 mm (IQR 18.6–30.2 mm) for ECGi and 31.0 mm (IQR 23.2–37.3 mm) for MCG (p=ns; Fig. C). Although localization error was numerically higher for MCG, differences were not statistically significant given the limited sample size.
Conclusions
Our preliminary results demonstrate the feasibility of using a novel, solid-state MCG sensor system for non-invasive atrial arrhythmia localization. The difference in localization accuracy between ECGi and MCG was not statistically significant in this initial animal cohort. This first-of-its-kind multimodal validation suggests that novel MCG technology may serve as a viable complementary mapping modality, warranting further validation in larger studies.