Magnetocardiography - measurement of the heart’s magnetic field - usually relies on SQUID (magnetometer-based) sensors to provide a single axis measurement made inside a shielded room. This requires a bulky and expensive installation, and the method does not collect useful information which could be gained from using a three-axis sensor.
A study by Sengottuvel et al in 2018 shows that fluxgates can be used, inside a shielded environment, to record the magnetic field associated with the heart’s electric activity. Trigger-locked averaging with the ECG signal enables the noise of the sensors to be greatly reduced. The additional information, gained by using three-component measurements, could help in validating the direction of the equivalent dipole associated with the heart’s activity.