Sengupta Shantanu P, Bansal Manish, Hofstra Leonard, Sengupta Partho P, Narula Jagat
Sengupta Hospital and Research Institute, Ravinagar, Nagpur, India.
Medanta-The Medicity, Gurgaon, India.
Int J Cardiovasc Imaging. 2017 Jan;33(1):69-82. doi: 10.1007/s10554-016-0977-y. Epub 2016 Sep 14.
The goal of this study was to evaluate the impact of pregnancy and labor on left ventricular (LV) myocardial mechanics using speckle tracking echocardiography (STE). Pregnancy is characterized by profound hormonal and hemodynamic alterations that directly or indirectly influence cardiac structure and function. However, the impact of these changes on left ventricular (LV) myocardial contractile function has not been fully elucidated. In this prospective, longitudinal study, 35 pregnant women underwent serial clinical and echocardiographic evaluation during each trimester and at labor. Two dimensional STE was performed to measure global LV longitudinal, circumferential and radial strain (GLS, GCS and GRS, respectively). Similar data obtained from 20 nulliparous, age-matched women were used as control. All strain values during pregnancy were adjusted for age and hemodynamic parameters. There was a progressive increase in heart rate, systolic and diastolic blood pressure, cardiac output and LV stroke-work during pregnancy. LV end-diastolic and end-systolic volumes also increased progressively but LV ejection fraction remained unaltered, except for slight reduction during the second trimester. Compared to the controls, GLS and GCS were reduced in the first trimester itself (GLS -22.39 ± 5.43 % vs. -18.66 ± 0.64 %, P 0.0002; GCS -20.84 ± 3.20 vs. -17.88 ± 0.09, P < 0.001) and remained so throughout the pregnancy and labor. In contrast, GRS showed an increase during pregnancy which peaked during the second trimester (24.18 ± 0.39 % vs. 18.06 ± 8.14 % in controls, P < 0.001). Alterations in loading conditions during pregnancy are associated with counterbalancing changes in the myocardial mechanics. LV longitudinal and circumferential strain are reduced whereas radial strain is increased. These counterbalancing changes serve to maintain overall LV ejection performance within a normal range and enable the maternal heart to meet the hemodynamic demands of pregnancy and labor.
本研究的目的是使用斑点追踪超声心动图（STE）评估妊娠和分娩对左心室（LV）心肌力学的影响。妊娠的特点是深刻的激素和血流动力学改变，这些改变直接或间接影响心脏结构和功能。然而，这些变化对左心室（LV）心肌收缩功能的影响尚未完全阐明。在这项前瞻性纵向研究中，35名孕妇在每个孕期及分娩时接受了系列临床和超声心动图评估。采用二维STE测量左心室整体纵向、圆周和径向应变（分别为GLS、GCS和GRS）。从20名未生育、年龄匹配的女性获得的类似数据用作对照。孕期所有应变值均根据年龄和血流动力学参数进行了调整。孕期心率、收缩压和舒张压、心输出量及左心室每搏功逐渐增加。左心室舒张末期和收缩末期容积也逐渐增加，但左心室射血分数保持不变，除了在孕中期略有降低。与对照组相比，孕早期GLS和GCS就已降低（GLS -22.39±5.43% vs. -18.66±0.64%，P<0.0002；GCS -20.84±3.20 vs. -17.88±0.09，P<0.001），且在整个孕期及分娩过程中均保持如此。相比之下，GRS在孕期增加，在孕中期达到峰值（24.18±0.39% vs. 对照组的18.06±8.14%，P<0.001）。孕期负荷条件的改变与心肌力学的平衡变化相关。左心室纵向和圆周应变降低，而径向应变增加。这些平衡变化有助于将左心室整体射血性能维持在正常范围内，并使母体心脏能够满足妊娠和分娩的血流动力学需求。
