Govindan R B, Lowery Curtis L, Campbell J Quaid, Best Thomas H, Murphy Pamela, Preissl Hubert T, Eswaran Hari
Graduate Institute of Technology, University of Arkansas, Little Rock, AR, USA.
Am J Obstet Gynecol. 2007 Jun;196(6):572.e1-7; discussion 572.e7. doi: 10.1016/j.ajog.2007.02.017.
The purpose of this study was to compare cardiac dynamics of high-risk and low-risk fetuses using beat to beat variability.
This study obtained 214 fetal magnetocardiography recordings from a group of high-risk fetuses with maternal conditions associated with placental insufficiency with the risk of developing intrauterine growth restriction or were already diagnosed with intrauterine growth restriction. For purpose of comparison, another 136 recordings were obtained from low-risk fetuses. The cardiac beat-to-beat intervals computed as RR intervals were analyzed from both groups using the mean and median interval, standard deviation of normal-to-normal intervals, root mean square of the successive differences, and the fraction of the normal-to-normal intervals (pNNx) that differ by more than the chosen tolerance level of 'x' milliseconds from the previous normal-to-normal intervals. Tests for significance between high-risk and low-risk fetuses were calculated using an independent samples t test within the following gestational age groups, 27-30 weeks, 31-35 weeks, and 36-40 weeks.
The root mean square of the successive differences, and the pNNx showed a significant difference between the low-risk and high-risk fetuses in the 31-35-week and the 36-40-week divisions. In the 31-35-week age division, low-risk fetuses had significantly lower root mean square of the successive differences, and pNN values than the high risk, but in the 36-40-week division, the low-risk fetuses had significantly higher root mean square of the successive differences, and pNN values.
Cardiac dynamics for fetuses of mothers at risk for placental insufficiency mature quicker than fetuses not at risk for placental insufficiency.
本研究旨在通过逐搏变异性比较高危和低危胎儿的心脏动力学。
本研究从一组高危胎儿中获取了214份胎儿心磁图记录，这些高危胎儿的母亲患有与胎盘功能不全相关的疾病，有发生宫内生长受限的风险或已被诊断为宫内生长受限。为了进行比较，从低危胎儿中又获取了136份记录。对两组计算出的RR间期的逐搏间期进行分析，使用平均和中位数间期、正常到正常间期的标准差、连续差值的均方根以及与前一个正常到正常间期相差超过选定的“x”毫秒耐受水平的正常到正常间期的分数（pNNx）。在以下孕周组（27 - 30周、31 - 35周和36 - 40周）内，使用独立样本t检验计算高危和低危胎儿之间的显著性检验。
连续差值的均方根和pNNx在31 - 35周和36 - 40周分组中显示高危和低危胎儿之间存在显著差异。在31 - 35周龄分组中，低危胎儿的连续差值均方根和pNN值显著低于高危胎儿，但在36 - 40周分组中，低危胎儿的连续差值均方根和pNN值显著更高。
胎盘功能不全风险母亲的胎儿心脏动力学比无胎盘功能不全风险的胎儿成熟得更快。
