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Abstract：
BACKGROUND: Coupling between left ventricle (LV) and left atrium (LA) plays a central role in the process of cardiac remodeling during aging and development of cardiac disease. The hydraulic force (HyF) is related to variation in size between LV and LA. The objectives of this study were to: (1) derive an estimate of left atrioventricular HyF using cine- Magnetic Resonance Imaging (MRI) in healthy subjects with a wide age range, and (2) study its relationship with age and conventional diastolic function parameters, as estimated by reference echocardiography.
METHODS: We studied 119 healthy volunteers (mean age 44 ± 17 years, 58 women) who underwent Doppler echocardiography and MRI on the same day. Conventional transmitral flow early (E) and late (A) LV filling peak velocities as well as mitral annulus diastolic longitudinal peak velocity (E\') were derived from echocardiography. MRI cine SSFP images in longitudinal two and four chamber views were acquired, and analyzed using feature tracking (FT) software. In addition to conventional LV and LA strain measurements, FT-derived LV and LA contours were further used to calculate chamber cross-sectional areas. HyF was approximated as the difference between the LV and LA maximal cross-sectional areas in the diastasis phase corresponding to the lowest LV-LA pressure gradient. Univariate and multivariate analyses while adjusting for appropriate variables were used to study the associations between HyF and age as well as diastolic function and strain indices.
RESULTS: HyF decreased significantly with age (R²=0.34, p < 0.0001). In addition, HyF was significantly associated with conventional indices of diastolic function and LA strain: E/A: R²=0.24, p < 0.0001; E\': R²=0.24, p < 0.0001; E/E\': R²=0.12, p = 0.0004; LA conduit longitudinal strain: R²=0.27, p < 0.0001. In multivariate analysis, associations with E/A (R2 = 0.39, p = 0.03) and LA conduit strain (R2 = 0.37, p = 0.02) remained significant after adjustment for age, sex, and body mass index.
CONCLUSIONS: HyF, estimated using FT contours, which are primarily used to quantify LV/LA strain on standard cardiac cine MRI, varied significantly with age in association with subclinical changes in ventricular filling. Its usefulness in cohorts of patients with left heart disease to detect LV-LA uncoupling remains to be evaluated.
METHODS: We studied 119 healthy volunteers (mean age 44 ± 17 years, 58 women) who underwent Doppler echocardiography and MRI on the same day. Conventional transmitral flow early (E) and late (A) LV filling peak velocities as well as mitral annulus diastolic longitudinal peak velocity (E\') were derived from echocardiography. MRI cine SSFP images in longitudinal two and four chamber views were acquired, and analyzed using feature tracking (FT) software. In addition to conventional LV and LA strain measurements, FT-derived LV and LA contours were further used to calculate chamber cross-sectional areas. HyF was approximated as the difference between the LV and LA maximal cross-sectional areas in the diastasis phase corresponding to the lowest LV-LA pressure gradient. Univariate and multivariate analyses while adjusting for appropriate variables were used to study the associations between HyF and age as well as diastolic function and strain indices.
RESULTS: HyF decreased significantly with age (R²=0.34, p < 0.0001). In addition, HyF was significantly associated with conventional indices of diastolic function and LA strain: E/A: R²=0.24, p < 0.0001; E\': R²=0.24, p < 0.0001; E/E\': R²=0.12, p = 0.0004; LA conduit longitudinal strain: R²=0.27, p < 0.0001. In multivariate analysis, associations with E/A (R2 = 0.39, p = 0.03) and LA conduit strain (R2 = 0.37, p = 0.02) remained significant after adjustment for age, sex, and body mass index.
CONCLUSIONS: HyF, estimated using FT contours, which are primarily used to quantify LV/LA strain on standard cardiac cine MRI, varied significantly with age in association with subclinical changes in ventricular filling. Its usefulness in cohorts of patients with left heart disease to detect LV-LA uncoupling remains to be evaluated.
摘要：
背景：左心室（LV）和左心房（LA）之间的耦合在心脏疾病衰老和发展过程中的心脏重塑过程中起着重要作用。液压力(HyF)与LV和LA之间的尺寸变化有关。本研究的目的是：（1）使用磁共振成像（MRI）在年龄范围很广的健康受试者中得出左房室HyF的估计值，（2）研究其与年龄和常规舒张功能参数的关系，通过参考超声心动图估计。
方法：我们研究了119名健康志愿者（平均年龄44±17岁，58名妇女）在同一天接受了多普勒超声心动图和MRI检查。常规的二尖瓣血流早期（E）和晚期（A）LV充盈峰值速度以及二尖瓣环舒张纵向峰值速度（E'）来自超声心动图。获得了纵向二腔和四腔的MRI电影SSFP图像，并使用特征跟踪(FT)软件进行分析。除了常规的LV和LA应变测量，FT导出的LV和LA轮廓进一步用于计算腔室横截面积。HyF近似为在舒张阶段对应于最低LV-LA压力梯度的LV和LA最大横截面积之间的差。在调整适当变量的同时，使用单变量和多变量分析来研究HyF与年龄以及舒张功能和应变指数之间的关联。
结果：HyF随年龄显著降低（R²=0.34，p<0.0001）。此外,HyF与舒张功能和LA应变的常规指标显着相关：E/A：R²=0.24，p<0.0001；E'：R²=0.24，p<0.0001；E/E'：R²=0.12，p=0.0004；LA导管纵向应变：R²=0.27，p<0.0001。在多变量分析中，与E/A（R2=0.39，p=0.03）和LA导管应变（R2=0.37，p=0.02）的相关性在调整年龄后仍然显着，性别,和体重指数。
结论：HyF，使用FT轮廓估计，主要用于量化标准心脏电影MRI上的LV/LA应变，随着年龄的增加，心室充盈的亚临床变化显著相关。其在左心脏病患者队列中检测LV-LA解偶联的有效性仍有待评估。
方法：我们研究了119名健康志愿者（平均年龄44±17岁，58名妇女）在同一天接受了多普勒超声心动图和MRI检查。常规的二尖瓣血流早期（E）和晚期（A）LV充盈峰值速度以及二尖瓣环舒张纵向峰值速度（E'）来自超声心动图。获得了纵向二腔和四腔的MRI电影SSFP图像，并使用特征跟踪(FT)软件进行分析。除了常规的LV和LA应变测量，FT导出的LV和LA轮廓进一步用于计算腔室横截面积。HyF近似为在舒张阶段对应于最低LV-LA压力梯度的LV和LA最大横截面积之间的差。在调整适当变量的同时，使用单变量和多变量分析来研究HyF与年龄以及舒张功能和应变指数之间的关联。
结果：HyF随年龄显著降低（R²=0.34，p<0.0001）。此外,HyF与舒张功能和LA应变的常规指标显着相关：E/A：R²=0.24，p<0.0001；E'：R²=0.24，p<0.0001；E/E'：R²=0.12，p=0.0004；LA导管纵向应变：R²=0.27，p<0.0001。在多变量分析中，与E/A（R2=0.39，p=0.03）和LA导管应变（R2=0.37，p=0.02）的相关性在调整年龄后仍然显着，性别,和体重指数。
结论：HyF，使用FT轮廓估计，主要用于量化标准心脏电影MRI上的LV/LA应变，随着年龄的增加，心室充盈的亚临床变化显著相关。其在左心脏病患者队列中检测LV-LA解偶联的有效性仍有待评估。
