**2. MCG definition and a brief insight to the magnetocardiography milestones**

Magnetocardiography allows recording magnetic fields without body invasion and any risks through the skin-surface methodology. The detected fields are created by the heart's electrical activity. However, the signal is pretty weak to export the samples for storing and assessment, making the technique demanding, e.g., typical level of a magnetic field generated by heart muscle currents is between 10<sup>10</sup> and 10<sup>12</sup> Tesla, whereas the Earth's magnetic field and the urban noise levels are considerably higher (**Figure 1**).

The 1963 study by McFee and Balue records the first magnetocardiograms [3]. To obtain the game-changing magnetocardiogram human data they applied a couple of coils, containing a ferromagnetic core wrapped around with thin copper wire for

**Figure 1.** *Specimens of generated magnetic fields.*

*Unshielded Magnetocardiography in Clinical Practice: Detection of Myocardial Damage… DOI: http://dx.doi.org/10.5772/intechopen.104924*

several million times in each, kept at room temperature. The experiments were held at a far-away country location, to avoid the urban electromagnetic hindrance. Nevertheless, the output of the detector had flaws.

The research progress for alloys in the early 70's introduced the use of superconducting magnetometers. Cohen at al. initially applied the superconducting quantum interference device (SQUID) magnetometer in a room with antimagnetic protection, to detect a magnetocardiogram with improved dimensional accuracy and better spatial-to-noise property.

These SQUID magnetometers remain the only available device to record MCGs. The MCG studies by Cohen at al. had an enormous contribution to the basics of MCG recordings methodology, but cannot be considered a clinically relevant study, even though physicians took part in a few measurements. Then, in the early 80's Germany, USA, Finland, Japan, and Italy had some preliminary clinical research studies. At that time, a sole SQUID sensor was moved step by step across the measurement layout at the area near the anterior torso. The first commercially-made multi-channel systems became available in 1988–1990 with the help of Siemens, Philips, and BTI cooperation. In fact, only properly shielded rooms could be used for those systems' operation (**Figure 2**).

Today, there are numerous MCG laboratories in countries such as the United States, Germany, China, South Korea, Italy, Finland, Great Britain, Russia, Japan, Taiwan, India, and others.

In Ukraine, research in the field of magnetocardiography was initiated by specialists of the Institute of Cybernetics. VM Glushkov NASU together with specialists of the Institute of Cardiology in 1992. These studies began with the use of a singlechannel MCG system. The work of the Kyiv group was pioneering from the very beginning because it was aimed at solving the most pressing problem—the diagnosis of coronary heart disease in difficult cases, i.e., in patients with uninformative results

**Figure 2.** *Philips multi-scan MCG system inside a highly-shielded room.*

**Figure 3.** *9-channel MCG-system (Cardiomox) in unshielded hospital setting.*

of routine tests such as ECG and resting echocardiography [4, 5]. Also, it is extremely important that the magnetocardiographic system developed by Ukrainian scientists can work in a normal unshielded room, which made the method of magnetocardiography suitable for wide clinical application (**Figure 3**).
