Richard D Gibbs

US Patent:

50424998, Aug 27, 1991

Filed:

Aug 2, 1990

Appl. No.:

7/561575

Inventors:

Thomas H. Frank - Crofton MD
Richard K. Gibbs - Laurel MD
Robert L. Wells - Odenton MD

International Classification:

A61B 50448

US Classification:

128698

Abstract:

A fetal heart rate monitor monitors weak fetal electrocardiogram signals in the presence of strong interfering material ECG complexes, general random background muscle noise, and 60 Hz power line noise. An electrocardiographic adaptive cancellation process to cancel the maternal ECG component from an abdominal ECG signal recorded from a pregnant subject's abdomen signal is processed using computer software. A set of easily movable maternal abdominal and thoracic ECG electrodes is used. An operator views the ECG data in an oscilloscope and optimally places the set of thoracic electrodes to adaptively cancel the maternal ECG signal from the signal separately derived from a movable abdominal electrocardiographic lead. The invention noninvasively obtains from the abdomen of a pregnant subject the fetal ECG signal, fetal heart rate, and accurate beat-to-beat fetal heart rate variability. Computer software provides cancellation of the maternal ECG component derived from a maternal abdominal ECG lead using a separate set of maternal thoracic ECG leads.