Computation of short-term fetal heart-rate variability from heart-rate waveforms

Clinical significance of short-term variability computed from heart-rate waveforms

“…Results produced by this method were found to correlate excellently with the DIFFERENTIAL INDEX, but the required computation time was reduced drastically compared with computation of the DIFFERENTIAL· INDEX from the fetal electrocardiogram [7]. Further, this method can be readily implemented on a small labor-room microcomputer without any additional hardware, and results can be made available in real-time.…”

“…We have previously described [4,7] a method for quantifiying STV in terms of beats per minute from the slowly-varying instantaneous FHR waveform rather than from the relatively rapidlyvarying fetal electrocardiogram. Results produced by this method were found to correlate excellently with the DIFFERENTIAL INDEX, but the required computation time was reduced drastically compared with computation of the DIFFERENTIAL· INDEX from the fetal electrocardiogram [7].…”

“…As described elsewhere [4,7], we define STV during some fixed time-window as the corrected maximum deviation of the instantaneous fetal heart rate from the heart-rate trend. This method was found to correlate excellently with the Differential Index, but proved to be much more efficient in terms of computational requirements.…”

“…In order to compute the adjacent R-R time intervals, the fetal EKG is generally processed by a computer, and the complexity of these analyses has limited the clinical application of this index. In order to circumvent this problem, we have developed, and described elsewhere [4,7], a method for computing STV from the slowly varying fetal heart rate waveform rather than from the relatively rapidly varying fetal electrocardiogram. This paper describes the clinical utilization of this technique, and presents results indicative of the significance of STV in intrapartal assessment.…”