Department of Medical Physics, Jeroen Bosch Hospital, 's-Hertogenbosch, The Netherlands.
Med Eng Phys. 2012 Apr;34(3):333-8. doi: 10.1016/j.medengphy.2011.07.025. Epub 2011 Sep 3.
Reliable monitoring of fetal condition often requires more information than is provided by cardiotocography, the standard technique for fetal monitoring. Abdominal recording of the fetal electrocardiogram may offer valuable additional information, but unfortunately is troubled by poor signal-to-noise ratios during certain parts of pregnancy. To increase the usability of abdominal fetal ECG recordings, an algorithm was developed that enhances fetal QRS complexes in these recordings and thereby provides a promising method for detecting the beat-to-beat fetal heart rate in recordings with poor signal-to-noise ratios. The method was evaluated on generated recordings with controlled signal-to-noise ratios and on actual recordings that were performed in clinical practice and were annotated by two independent experts. The evaluation on the generated signals demonstrated excellent results (sensitivity of 0.98 for SNR≥1.5). Only for SNR<2, the inaccuracy of the fetal heart rate detection exceeded 2 ms, which may still suffice for cardiotocography but is unacceptable for analysis of the beat-to-beat fetal heart rate variability. The sensitivity and positive predictive value of the method in actual recordings were reduced to approximately 90% for SNR≤2.4, but were excellent for higher signal-to-noise ratios.
可靠的胎儿状况监测通常需要比胎心监护（胎儿监测的标准技术）提供的更多信息。腹部记录胎儿心电图可能会提供有价值的额外信息，但不幸的是，在怀孕的某些阶段，信号噪声比会很差。为了提高腹部胎儿心电图记录的可用性，开发了一种算法，该算法可以增强这些记录中的胎儿 QRS 复合体，从而为在信噪比较差的记录中检测逐拍胎儿心率提供了一种很有前途的方法。该方法在具有受控信噪比的生成记录以及在临床实践中进行并由两位独立专家注释的实际记录上进行了评估。对生成信号的评估表明了出色的结果（SNR≥1.5 时的灵敏度为 0.98）。仅在 SNR<2 时，胎儿心率检测的不准确性超过 2 毫秒，这对于胎心监护可能还足够，但对于逐拍胎儿心率变异性的分析是不可接受的。对于 SNR≤2.4 的实际记录，该方法的灵敏度和阳性预测值降低到约 90％，但对于更高的信噪比则非常出色。
