Magnetocardiography (MCG) is a technique to measure the magnetic fields produced by electrical activity in the heart using extremely sensitive devices such as the superconducting quantum interference device (SQUID).


  • Built by Elekta Neuromag Ltd., Helsinki (at present, MEGIN Oy).
  • 99 channels, comprised of 33 three-channel units with
    • two orthogonal planar gradiometers and
    • one magnetometer in each.
  • Cylindrically curved bottom.
  • Boil-off under 6 l/day.
  • MCG gantry moves on an air cushion.

Fields of MCG research at BioMag

  • Atrial arrhythmias, atrial fibrillation
  • Myocardial ischemia
  • Estimation of the risk of sudden cardiac death
  • Repolarization disorders
  • Congenital long-QT syndrome
  • Left-ventricular hypertrophy
  • Locating myocardiac arrhythmogenic foci
  • Wolff-Parkinson-White (WPW) syndrome
    • 3D localization accuracy of the overt accessory pathway in WPW syndrome can be determined with an accuracy of 1–1.5 cm

Preoperative information has helped in the planning of ablative therapy.

Malignant ventricular tachyarrhythmias after myocardial infarction have low-amplitude high-frequency electromagnetic activity, so called late fields, at the end of the ventricular depolarization phase. These signals are absent in patients without arrhythmic events after myocardial infarction.
Similar abnormal ventricular activity can also be found in patients with cardiomyopathy and ventricular tachyarrhythmias.

Long-QT patients have an inhomogeneous pattern of repolarization in MCG, clearly distinguishable from the normal pattern of their healthy relatives.

In summary, multichannel MCG seems a powerful new clinical tool for identifying risk and for locating the foci in patients with life-threatening arrhythmias.