Magnetocardiography (MKG)

Cellular activities, especially those of muscles and nerve cells, are fundamentally associated with collective electrical activity. These currents generate a spatially and temporally variable biomagnetic field, which can also be detected outside the heart muscle with a suitably sensitive magnetic field sensor. In contrast to the electrical signals of an ECG, which depend on the specific (also time-varying!) electrical conductivity of the tissue of the outer skin areas, cardiac magnetic fields can also be measured outside the body without touching the test person himself.

MKG measures the sum signal of all electrophysiological currents flowing in the heart muscle. In this way, internal eddy currents can even be measured from the back of the heart, thus providing essential additional information for cardiac diagnostics, but to which the ECG can unfortunately be blind. The BSPM method (Body Surface Potential Mapping), which is based on the ECG principle, therefore also falls significantly short of the signal-to-noise ratio achieved with MKG.

Thus, MKG can have a considerable advantage especially in the diagnosis of coronary heart disease and myocardial infarction (so-called ischaemic heart disease) and in the risk stratification of sudden cardiac death. By detecting ischaemia early, effective therapy can be indicated in time to prevent a heart attack. The risk of cardiac arrhythmias (ventricular tachycardia VT), which can lead to sudden cardiac death, can be evaluated early using MKG. With this information, the attending physician can at the same time reduce the number of incorrect admissions to the hospital.

Supracon supplies components as well as complete measuring systems for magnetocardiography (MHC), such as the 9-channel magnetocardiography system developed in cooperation with Cryoton and Softmag and presented here.

Clinical tests provide evidence that the current distribution on the heart muscle determined with MKG provides a very detailed picture of the functional state of the heart. The spatial resolution that can be achieved with MKG is significantly better than the ECG-based method of BSPM (Body Surface Potential Mapping). At the same time, MKG is a method with an extremely fast temporal resolution of less than one millisecond. The comparison of MKG current distribution recordings of a patient under stress (e.g. injection of dobutamine) or under physical strain (ergometer bicycle) with corresponding recordings in the patient's resting state provides the cardiologist with very important information for the diagnosis of functional disorders even before an infarction has occurred! This is especially true for the diagnosis of ischaemia in patients with CAD (coronary artery disease).