Detection of atrial-flutter and atrial-fibrillation waveforms by fetal magnetocardiogram

A. Kandori, T. Hosono, T. Kanagawa, S. Miyashita, Y. Chiba, M. Murakami, T. Miyashita, K. Tsukada

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


Two cases of fetal tachycardia are reported: atrial flutter and fibrillation. The waveforms from each case were detected by fetal magnetocardiograms (FMCGs) using a 64-channel superconducting quantum interference device (SQUID) system. Because the magnitude of supraventricular arrhythmia signals is very weak, two subtraction methods were used to detect the fetal MCG waveforms: subtraction of the maternal MCG signal, and subtraction of the fetal QRS complex signal. It was found that atrial-flutter waveforms showed a cyclic pattern and that atrial-fibrillation waveforms showed f-waves with a random atrial rhythm. Fast Fourier transform analysis determined the main frequency of the atrial flutter to be about 7 Hz, and the frequency distribution of atrial fibrillation consisted of small, broad peaks. To visualise the current pattern, current-arrow maps, which simplify the observation of pseudo-current patterns in fetal hearts, of the averaged atrial flutter and fibrillation waveforms were produced. The map of the atrial flutter had a circular pattern, indicating a re-entry circuit, and the map of the atrial fibrillation indicated one wavelet, which was produced by a micro-re-entry circuit. It is thus concluded that an FMCG can detect supraventricular arrhythmia, which can be characterised by re-entry circuits, in fetuses.

Original languageEnglish
Pages (from-to)213-217
Number of pages5
JournalMedical and Biological Engineering and Computing
Issue number2
Publication statusPublished - Jan 1 2002
Externally publishedYes


  • Atrial fibrillation
  • Atrial flutter
  • Fetal magnetocardiogram

ASJC Scopus subject areas

  • Biomedical Engineering
  • Computer Science Applications


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