High-resolution imaging of cardiac biomagnetic fields using a low-transition-temperature superconducting quantum interference device microscope Available to Purchase

We have developed a multiloop low-temperature superconducting quantum interference device sensor with a field sensitivity of $450 fT/Hz−1/2$ for imaging biomagnetic fields generated by action currents in cardiac tissue. The sensor has a diameter of 250 μm and can be brought to within 100 μm of a room-temperature sample. Magnetic fields generated by planar excitation waves are associated with a current component parallel to the wave front, in agreement with predictions of the bidomain model. Our findings provide a new basis for interpreting the magnetocardiogram.