Abstract
Our aim in this study is to obtain images of current distributions including morphological information on the heart. Such images are obtained by projecting two-dimensional (2-D) current-arrow maps, calculated from magnetocardiogram (MCG) signals, onto a three-dimensional (3-D) heart model obtained from magnetic resonance (MR) images. We used a superconducting quantum interference device (SQUID) system to measure the normal component (Bz) of MCG signals. The signals were measured at 64 points with an 8×8 array above the chest, and were acquired at a sampling rate of 1kHz. The MR images were obtained by scanning coronal planes with a 6mm vertical separation. We made individual heart models for three healthy subjects from heart-outline points extracted from the MR images of the subjects. Current-arrow maps were calculated by taking the orthogonal partial derivatives of the MCG signal normal component. The current-arrow maps for three healthy subjects were then projected on the individual heart models by means of displacement-free mapping of the current vectors to the corresponding heart-outline points. The currentarrow maps, which were projected to the individual heart model, strongly reflect the respective electrophysiological phases (P-wave, QRS-complex, and T-wave), and give us a clear view of the anatomical sites of activation in the heart.
