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Magnetocardiogram of a Healthy Individual 1 Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA Patient With Normal Coronary Arteries Demographic data Basic parameters Gender Age BMI HR BP EF female 65 31 80 130:80 -- Risk factors DM HT Prior MI Prior CAD Smoker HLP no no no no yes no Other test results ECG ECHO TNI Indication normal normal normal ACS Coronary Angiography LAD stenosis location LCX stenosis location RCA stenosis location 2 Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA Atrial Activity of the Normal Control The vector in the animated colour magnetic field map depicts the location and orientation of a magnetic dipole that is equivalent to the source of the electric activity. Interpretation of the vector’s dynamics (changes over time) helps understanding the underlying electrical process. 3 Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA Right Atrial Depolarization The history of vectors indicates that the electric activity in the right atrium is uniform and focused. 4 Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA Left Atrial Depolarization A clean transition of electrical activity from right to left atrium is visible. 5 Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA Atrial Repolarization Electric activity during atrial repolarization is directed opposite to depolarization. Due to lower signal strength its interpretation requires experience. In case of an accessory pathway a second dipolar structure would be visible. Note: for better visibility only the beginning of atrial repolarization is shown. 6 Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA Depolarization of the Intraventricular Septum The AV node carries the activity to the intraventricular septum, which depolarizes. The electric current propagates along the septum until it reaches the apex. 7 Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA Ventricular Depolarization The ventricles depolarize. The map shows a superposition of LV and RV activity. The LV free wall’s magnetic signature dominates over that of the RV. However, the effect of a conduction abnormality in the RV would be visible indirectly through a change in pattern and polarity. 8 Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA Late Ventricular Depolarization The electric activity moves from anterior to posterior indicated by an increasing distance of the two maxima. Note that the polarity of the magnetic field flips by 180 degrees. The 3D animation nicely reflects the spatial propagation of the vector. 9 Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA The ‘ST Segment’ The ST segment in the normal MCG is rather flat: MCG traces in the butterfly plot are bundled densely. The map often shows a random distribution of magnetic fields. This is due to the fact that cardiac electric activity is close to zero thus leading to a very small signal to noise ratio. In the present case it can be concluded that the remaining activity in the ST segment is mostly due to non-cardiac sources (noise). 10 Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA Ventricular Repolarization In the normal heart repolarization usually begins in the last area of the heart to have been depolarized, and then travels backward, in the opposite direction of the wave of depolarization. The approaching wave of depolarization and the receding wave of repolarization generate similar field maps both in pattern and polarity. The normal heart shows a uniform, homogenous, and stable field distribution. 11 Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA