Mag·ne·to·car·di·og·ra·phy
[mag-ˌnēt-ō-ˌkärd-ē-ˈäg-rə-fē]
A medical imaging technique to measure the magnetic fields produced by the heart’s electrical activity using extremely sensitive devices.
First discovered in 1963, MCG is a medical imaging technique that measures the magnetic fields naturally generated by the electrical activity of the heart. The unique sensitivity of MCG enables physicians to detect and characterize even the smallest alterations in cardiac electrophysiology that may arise as a result of heart disease.
Timeline of MCG
Unfortunately, early versions of MCG devices were too bulky, expensive, and finicky to be useful in clinical practice, limiting their adoption to mostly academic institutions.
Genetesis’ CardioFlux MCG resolves these barriers by integrating the latest advances in sensing technology and machine learning to produce an MCG device requiring only a standard-sized room (without magnetic shielding) and a single standard outlet.
The most well-known output of MCG is the magnetic field map (MFM). An MFM appears as a 3D surface with peaks and valleys that characterize magnetic field intensity and direction. The heart’s electrical conduction gives rise to the net current vector and corresponding magnetic dipoles, defined by the most positive and most negative magnetic field values captured.
During ventricular repolarization, a normal MFM should exhibit a singular current pattern that results in a single positive and negative pole, each appearing distinct and clearly defined.
In patients with functional ischemia, a multipolar pattern will often appear during repolarization, indicating heterogeneity and alterations in the amplitude and rate of action potentials in affected tissue.
MCG is believed to detect cardiac dysfunction early on in the ischemic cascade because of its sensitivity to changes in ion conduction and action potential. One of the major advantages of MCG is that magnetic fields are not distorted as they travel through tissue, unlike electrical currents that are directly measured using EKG. Additionally, MCG has demonstrated higher sensitivity to tangential and vortex currents which provide ischemia-rich information.
Several decades of research and multiple peer-reviewed studies around the world have clearly proven MCG’s ability to diagnose coronary artery disease (CAD), where MCG has demonstrated accuracy rivaling - and in some cases, even outperforming - current standard of care stress testing.
Emerging data from a new study conducted by Genetesis and presented at the ESC 2022 meeting in Barcelona demonstrated how MCG may have the ability to diagnose coronary microvascular dysfunction (CMD) in patients with ischemia and non-obstructive arteries (INOCA), a disease understood to be “invisible” to most forms of clinically available stress testing.
Like other modern imaging technologies, MCG has the potential to be far more than a single-purpose diagnostic. Here are three major areas where MCG has been and continues to be explored.
