Superimposing the atrial excitation onto the MRI planes

The magnetocardiographic three-dimensional source localization using superconducting quantum interference device (SQUID) gradiometer has an excellent spatial and temporal resolution. In the present study, the signal averaged P wave of the magnetocardiogram (MCG) was recorded by 7-channel SQUID gradiometer and the dipole trajectory of the atrial activation was projected onto MRI planes. The first half of the atrial activation of the P wave is located in the right atrium and the latter half in the left atrium. The present study was in good agreement with the distribution of the excitatory process of the isolated human heart reported by Durrer et al, suggesting that this method is useful for analysis of atrial activities. (author)