Multi-channel magnetocardiography for detecting beat morphology variations in fetal arrhythmias

Over the last few years, a number of studies have shown that fetal magnetocardiography (fMCG) is useful in describing fetal cardiac activity. A 55-channel MCG system in Ulm was used to record fetal cardiac activity in 12 pregnant women (with normal fetal heart activity in echocardiography) and in 5 pregnant women in whom the echocardiography showed fetal arrhythmias.

The recorded MCG data were treated in order to eliminate the maternal signal and three MCG channels with the best signals were used to emulate a standard electrocardiogram (ECG) recording so that standard MCG analysis could be performed.

The results in assessing fetal electrophysiology, demonstrating its potential, are presented here for two fetuses with recorded supraventricular extrasystoles (SVES) and for one with ventricular extrasystoles (VES). Concerning the SVES, the analysis software OMEGA was able to separate three different beat morphologies. The VES could be detected exactly and have been confirmed by postnatal ECG.

The beat morphology and the beat-to-beat variations allow new insights into the electrophysiology of the fetal heart.