1. 1 Magnetocardiogram of a Healthy Individual Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA

2. 2 Patient With Normal Coronary Arteries Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA Demographic dataBasic parameters GenderAgeBMIHRBPEF female653180130:80-- Risk factors DMHTPrior MIPrior CADSmokerHLP no yesno Other test results ECGECHOTNIIndication normal ACS Coronary Angiography LADLCXRCA stenosislocationstenosislocationstenosislocation

3. 3 Atrial Activity of the Normal Control Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA 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.

4. 4 Right Atrial Depolarization Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA The history of vectors indicates that the electric activity in the right atrium is uniform and focused.

5. 5 Left Atrial Depolarization Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA A clean transition of electrical activity from right to left atrium is visible.

6. 6 Atrial Repolarization Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA 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.

7. 7 Depolarization of the Intra- ventricular Septum Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA The AV node carries the activity to the intraventricular septum, which depolarizes. The electric current propagates along the septum until it reaches the apex.

8. 8 Ventricular Depolarization Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA 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.

9. 9 Late Ventricular Depolarization Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA 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.

10. 10 The ‘ST Segment’ Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA 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).

11. 11 Ventricular Repolarization Copyright © 2005 CardioMag Imaging, Inc. (CMI) 450 Duane Av, Schenectady, NY 12304, USA 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.