<unk>  <unk>  is a technique to measure the magnetic fields produced by electrical currents in the heart using extremely sensitive devices such as the superconducting quantum interference device (SQUID). If the magnetic field is measured using a multichannel device, a map of the magnetic field is obtained over the chest; from such a map, using mathematical algorithms that take into account the conductivity structure of the torso, it is possible to locate the source of the activity. For example, sources of abnormal rhythms or arrhythmia may be located using<unk> .
Magnetocardiography
Ballistocardiography
Impedance cardiography
Electrical cardiometry
Phonocardiogram
Vectorcardiography
Electrocorticography
Electrocochleography