Department of Neonatology, The Rotunda Hospital, Dublin, Ireland.
The Labatt Family Heart Centre, The Hospital for Children, Toronto, Ontario, Canada.
J Am Soc Echocardiogr. 2015 Jul;28(7):808-17.e1. doi: 10.1016/j.echo.2015.02.015. Epub 2015 Mar 26.
There is a paucity of data on left ventricular (LV) rotational physiology, twist, and torsional mechanics in preterm infants. The principal aims of the present study were to assess the feasibility and reproducibility of measuring LV rotation, twist, and torsion in preterm infants (<29 weeks' gestation) using two-dimensional speckle-tracking echocardiography and to examine the changes in those parameters over the first week after birth.
This was a prospective observational study involving preterm infants <29 weeks' gestation. Echocardiographic evaluations were performed on days 1, 2, and 5 to 7 after delivery. LV basal and apical rotation, LV twist, LV twist rate (LVTR), and LV untwist rate (LVUTR) were measured from the basal and apical short-axis parasternal views and calculated using two-dimensional speckle-tracking echocardiography. Torsion was also calculated by normalizing LV twist to LV end-diastolic length. One-way repeated-measures analysis of variance was used to compare values across the three time points. Intra- and interobserver reproducibility were assessed using Bland-Altman analysis and the intraclass correlation coefficient.
Fifty-one infants with a mean ± SD gestational age of 26.8 ± 1.5 weeks and a mean birth weight of 945 ± 233 g were included. There was high intra- and interobserver reproducibility for basal and apical rotation, LV twist, and LV torsion, with intraclass correlation coefficients ranging from 0.78 to 0.96 (P < .001 for all). Intra- and interobserver intraclass correlation coefficients for LVTR and LVUTR ranged from 0.70 to 0.88 (P < .001 for all). Apical rotation remained constant over the first week of age in a positive counterclockwise fashion (11.8 ± 5.0° vs 12.1 ± 6.1° vs 11.7 ± 8.3°, P = .92). Basal rotation changed from counterclockwise on day 1 to clockwise on day 7 (median, 5.5° [interquartile range, -0.3° to 8.3°] vs 4.0 [interquartile range, -4.7° to 7.2°] vs -4.5° [interquartile range, -5.8° to -2.3°], P < .001), with resultant net increases in twist and torsion (P < .05). There was no change in LVTR (P = .60), but LVUTR increased across the same time period (P = .01).
Assessment of twist, LVTR, and LVUTR is feasible in preterm infants, with acceptable reproducibility. There are increases in LV twist and torsion in addition to LVUTR, suggesting changes in LV mechanics during the first week of age.
关于左心室（LV）旋转生理学、扭转和扭转力学的早产儿数据很少。本研究的主要目的是使用二维斑点追踪超声心动图评估早产儿（<29 周妊娠）的 LV 旋转、扭转和扭转测量的可行性和可重复性，并研究这些参数在出生后第一周的变化。
这是一项前瞻性观察研究，涉及<29 周妊娠的早产儿。在分娩后第 1、2 和 5-7 天进行超声心动图评估。从基底和心尖短轴胸骨旁视图测量 LV 基底和心尖旋转、LV 扭转、LV 扭转率（LVTR）和 LV 解旋率（LVUTR），并使用二维斑点追踪超声心动图计算。扭转也通过将 LV 扭转归一化为 LV 舒张末期长度来计算。采用单因素重复测量方差分析比较三个时间点的值。使用 Bland-Altman 分析和组内相关系数评估观察者内和观察者间的可重复性。
纳入 51 名平均胎龄为 26.8 ± 1.5 周、平均出生体重为 945 ± 233 g 的婴儿。基底和心尖旋转、LV 扭转和 LV 扭转具有很高的观察者内和观察者间可重复性，组内相关系数范围为 0.78 至 0.96（P <.001）。LVTR 和 LVUTR 的观察者内和观察者间组内相关系数范围为 0.70 至 0.88（P <.001）。心尖旋转在出生后第一周以顺时针方向保持不变（11.8 ± 5.0° vs 12.1 ± 6.1° vs 11.7 ± 8.3°，P =.92）。基底旋转从第 1 天的逆时针变为第 7 天的顺时针（中位数，5.5°[四分位距，-0.3°至 8.3°] vs 4.0[四分位距，-4.7°至 7.2°] vs -4.5°[四分位距，-5.8°至-2.3°]，P <.001），导致扭转和扭转增加（P <.05）。LVTR 没有变化（P =.60），但 LVUTR 在同一时间段增加（P =.01）。
在早产儿中，评估扭转、LVTR 和 LVUTR 是可行的，具有可接受的可重复性。除了 LVUTR 增加外，LV 扭转和扭转也增加，提示 LV 力学在出生后第一周发生变化。
