Magnetocardiography to screen adults with arrhythmogenic cardiomyopathy: A feasibility study

Background: Arrhythmogenic cardiomyopathy (ACM) is a primary cardiomyopathy associated with mechanical and electrical dysfunction, making diagnosis a clinical challenge. This feasibility study investigates whether Optically Pumped Magnetometer (OPM)-based magnetocardiography (MCG), which offers complementary spatial information about cardiac electrical activity compared to ECG, can identify biomarkers in ACM patients. Methods: MCG data were acquired using an array of 16 OPMs. After signal processing and artifact removal via Independent Component Analysis (ICA), two-dimensional vector magnetocardiogram (VMCG) projections were constructed for the QRS and T-wave segments. Geometric features derived from the VMCG loops were compared between groups using Welch's t-test. To ensure statistical robustness, Monte Carlo simulations modeled measurement uncertainty, correlation analyses assessed potential age-related confounding, and post-hoc false discovery rate (FDR) correction was applied to account for repeated sensor-wise comparisons. Results: We enrolled 9 ACM patients and 12 healthy controls. The main finding was signal attenuation in ACM patients compared to healthy controls, as evidenced by smaller VMCG loop dimensions. This effect was most pronounced during the T-wave segment, where ACM patients exhibited a smaller convex hull area. During the QRS complex, reductions in maximum signal amplitude were observed. Correlation analysis in healthy controls revealed no significant association between age and signal strength. No significant differences were found in the ST segment. Conclusion: Our findings suggest that flexible, room-temperature OPM-based MCG may non-invasively detect electrophysiological alterations in ACM affecting both ventricular repolarization (T-wave area) and depolarization (QRS amplitude), with repolarization changes being particularly prominent. Further evaluation in larger studies is warranted.