Magnetocardiography (MCG) is a non-invasive technique that measures the extremely weak magnetic field (~10⁻¹² T) generated by the heart’s electrical activity.
It relies on Maxwell’s equations, where ionic currents in cardiac tissue produce magnetic fields, detected using ultra-sensitive sensors such as SQUID magnetometers in shielded environments.
Compared to ECG, MCG is less affected by tissue conductivity and allows more accurate reconstruction of current flow geometry in the heart.
Limitation: due to very low signal-to-noise ratio, reliable measurements are feasible only at close range (cm–dm scale).