A case of fetal complete heart block recorded by magnetocardiography, ultrasonography and direct fetal electrocardiography.

Fetal magnetocardiograms (FMCGs) were recorded in a case of fetal complete heart block (CHB) from the 30th to the 37th week of gestation using the multichannel SQUID system (Hitachi, Japan). M-mode ultrasonography and direct fetal electrocardiography using needle electrodes revealed fetal CHB. We identified independent fetal P-waves and QRS complexes in the FMCG recorded in the 32nd week of gestation when the fetal atriums were close to the FMCG sensor. We also recorded FMCG P-waves in the 37th week of gestation when the fetal heart was larger. Fetal heart position and size are important for obtaining a useful FMCG. To establish FMCG as a diagnostic tool of fetal arrhythmia, comparative studies with FECG are needed.