Visualization of the Current Density Distribution in MCGs of a WPW Syndrome Patient Using Independent Component Analysis
Koichiro KOBAYASHI, M. Yoshizawa, Kenichi Yamazaki, Y. Uchikawa, Kenta Nakai · Journal of the Magnetics Society of Japan · 2004
We measured magnetocardiograms (MCGs) of a normal subject and a Wolff-Parkinson-White (WPW) syndrome patient. It is generally difficult to separate the accessory pathway and normal conduction system by visualization of the current density distribution (VCDD), because the VCDD has a wide range. Independent component analysis (ICA) is a useful method for separating independent signals from overlapping signals. In this study, the source of the accessory pathway was estimated by using ICA to obtain the VCDD.First, principal component analysis was applied to the MCG as a pre-process and ICA was performed on the same dominant components. The activity of the accessory pathway was extracted from these components, and the waveform was reconstituted.The VCDD was displayed from the onset of the delta wave (150 ms) to the R wave region (220 ms). The positions of the current density (a) without the ICA and (b) with the ICA were particularly different at 160 ms and 180 ms. The current density with the ICA remained in the same position, D5, from 160 ms to 220 ms, and was also about 2 cm different from the current density without the ICA.It was confirmed that ICA is useful method for estimating the VCDD of an MCG of a WPW syndrome patient.