Magnetocardiography in the diagnosis of fetal arrhythmia.

Objective: To examine the possible use of magnetocardiography in the diagnosis of fetal arrhythmias.

Design: Investigation of routinely examined pregnant women, as well as women referred because of arrhythmias or other reasons.

Participants: Sixty-three women between the 13th and 42nd week of pregnancy.

Methods: Recording of 189 fetal magnetocardiograms, of which 173 traces (92%) demonstrated sufficient fetal signal strength to permit evaluation. After digital subtraction of the maternal artefact, all fetal complexes were identified and the recording was examined for arrhythmic events.

Results: Short bradycardic episodes, not associated with any pathological condition, were found in 26% of all recordings, usually in mid-pregnancy. In 12 cases, isolated extrasystoles of no clinical importance could be identified. There were nine traces which revealed multiple arrhythmias including ventricular and supraventricular ectopic beats, bigeminy and trigeminy, sino-atrial block and atrio-ventricular conduction disturbances. Furthermore, two cases with tachycardia were found.

Conclusion: Magnetocardiography offers a simple noninvasive method for examination of the fetal cardiac electrophysiological signal. It may thus be useful in the identification and classification of clinically relevant arrhythmia and aid in decisions concerning treatment.