Feasibility of Noninvasive Atrial and Ventricular Activation, Conduction-Velocity, and Site-of-Origin Mapping with Solid-State Magnetocardiography: A Preclinical Validation Study
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Background
Characterizing cardiac activation by its site of origin, propagation, and conduction velocity underlies arrhythmia diagnosis and management, but invasive electrophysiology (EP) mapping requires vascular access, fluoroscopy, and sedation. Magnetocardiography (MCG) enables contactless mapping, and recent solid-state sensors remove the cost, cryogenic, and shielding barriers of legacy systems. We assessed the feasibility of a novel solid-state MCG system for noninvasive arrhythmia site-of-origin (SOO) localization and activation reconstruction, benchmarked against electrocardiographic imaging (ECGi).
Methods
In nine swine implanted with right atrial and right ventricular pacing leads, we recorded MCG and ECGi simultaneously during atrial and ventricular pacing. Invasive epicardial contact EP mapping provided the activation-time reference and MRI-derived lead-tip location the SOO reference. Local activation time (LAT), conduction velocity (CV), and SOO were compared on a co-registered chamber mesh. SOO error was the Euclidean distance to the MRI lead tip; LAT and CV agreement with EP were quantified by Pearson r and compared using Wilcoxon signed-rank tests.
Results
Across 17 datasets (8 atrial, 9 ventricular), median SOO error was lower for MCG than ECGi in the atrium (19.6 vs 31.2 mm; p=0.023) and ventricle (12.0 vs 26.1 mm; p=0.074). LAT agreement with EP was comparable between modalities and higher in the ventricle (MCG r=0.63; ECGi r=0.68) compared with the atrium (MCG r=0.40; ECGi r=0.53), each correlating with invasive EP mapping above chance. CV agreement was modest and numerically higher for MCG in the ventricle.
Conclusions
Solid-state MCG was feasible for noninvasive site-of-origin localization and activation mapping, with accuracy comparable to ECGi, motivating larger prospective studies to define its clinical role in noninvasive mapping.
Clinical Perspective
What Is Known
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Invasive electrophysiology mapping is the reference standard for localizing the arrhythmia site of origin and characterizing cardiac activation, but it requires vascular access, fluoroscopy, and prolonged sedation within the electrophysiology laboratory.
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Existing noninvasive options have important limitations: electrocardiographic imaging depends on concomitant thoracic imaging, size-dependent vest fit, and torso-conductivity modeling, while legacy magnetocardiography has required costly cryogenic and magnetically shielded infrastructure.
What the Study Adds
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In a preclinical large-mammal model referenced to invasive electrophysiology and MRI, a novel contactless solid-state magnetocardiography system feasibly localized atrial and ventricular sites of origin and reconstructed activation without body-surface electrodes.
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Magnetocardiography localized the site of origin more accurately than ECGi in the atrium, and showed numerically lower localization error in the ventricle.
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Magnetocardiography displayed activation-time and conduction-velocity agreement with invasive electrophysiology comparable to electrocardiographic imaging in both chambers.
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Solid-state magnetocardiography may offer a scalable, noninvasive approach for preprocedural localization and complementary activation mapping, motivating larger prospective clinical validation.
