Electrical Inhibition (EI) of Preterm Uterine Contractions: Electrical and Mechanical Activity

Abstract

Background: Uterine smooth muscles produce bundles of electrical activity or electromyogram (EMG) preceding and controlling uterine mechanical contractions. Uterine preterm and term contractions are a function of contraction frequency and force. Uterine tocodynamometry (TOCO) monitors mechanical contraction frequency objectively by peak-to-peak (P-P) interval but force only subjectively by amplitude. Computer algorithms convert uterine EMG into an electrohysterogram (EHG) a more objective measure of contraction force (fig. 1A and 1B) than TOCO. Analysis of the EMG power spectral density (PSD) isolates the electrical bundle peak frequency (fp). Uterine fp indicates maximum contraction activity and is reduced with pharmaceutical tocolytics. An EI current delivered by an electrical pacemaker i.e. an electroceutical tocolytic may be …