EA 4278, "Laboratoire de Pharm-Ecologie Cardiovasculaire", Faculty of Sciences, University of Avignon, Avignon, France.
Obesity (Silver Spring). 2012 Dec;20(12):2397-405. doi: 10.1038/oby.2012.111. Epub 2012 May 7.
The prevalence of severe obesity is increasing worldwide in adolescents. Whether it is associated with functional myocardial abnormalities remains largely unknown, potentially because of its frequent association with other cardiovascular risk factors and also use of insensitive techniques to detect subclinical changes in myocardial function. We used 2D vector velocity imaging (VVI) to investigate early changes in left ventricular (LV) myocardial function in youths with isolated severe obesity. Thirty-seven asymptomatic severely obese adolescents free of diabetes and hypertension, and 24 lean controls were enrolled. LV longitudinal, basal, and apical circumferential strain, strain rate (SR), rotations, and LV twist were measured. Obese adolescents had greater LV mass and reduced systolic and early diastolic tissue Doppler imaging (TDI) velocities than lean counterparts. L strain (-24%) and systolic and early diastolic SR were also diminished in the obese, whereas no intergroup differences existed for the circumferential deformation indexes. LV twist was more pronounced in the obese (+1.7°, P < 0.01) on account of greater apical rotation only (4.1 ± 0.9 vs. 5.2 ± 1.2°, P < 0.01), potentially compensating for the loss in longitudinal function. Systolic-diastolic coupling, an important component of early filling and diastolic function, was maintained with severe obesity. No intergroup differences were reported regarding time to peak values for all VVI indexes highlighting that dynamics of strain and twist/untwist along the cardiac cycle was preserved with severe obesity. Isolated severe obesity in adolescents, at a preclinical stage, is associated with changes in myocardial deformation and torsional mechanics that could be in part related to alterations in relaxation and contractility properties of subendocardial fibers.
全球青少年重度肥胖症的患病率正在上升。尽管其与心肌功能异常密切相关，但目前尚不完全清楚其是否与其他心血管危险因素有关，也可能是因为其常与其他心血管危险因素有关，而且还因为使用了不敏感的技术来检测心肌功能的亚临床变化。我们使用二维向量速度成像（VVI）技术研究了单纯性重度肥胖青少年左心室（LV）心肌功能的早期变化。共纳入 37 名无糖尿病和高血压的无症状重度肥胖青少年和 24 名瘦对照者。测量了 LV 纵向、基底和心尖周向应变、应变率（SR）、旋转和 LV 扭转。肥胖青少年的 LV 质量更大，收缩期和早期舒张期组织多普勒成像（TDI）速度较瘦对照组降低。与瘦对照组相比，肥胖组的 L 应变（-24%）和收缩期及早期舒张期 SR 也降低，而周向变形指标两组间无差异。LV 扭转在肥胖组更为明显（+1.7°，P < 0.01），这主要是由于心尖旋转增加（4.1 ± 0.9 比 5.2 ± 1.2°，P < 0.01），可能补偿了纵向功能的丧失。收缩-舒张偶联是早期充盈和舒张功能的一个重要组成部分，在重度肥胖症中仍能维持。所有 VVI 指标的峰值时间差异无统计学意义，提示在整个心动周期中应变和扭转/解扭的动力学在重度肥胖症中得以保持。青少年的单纯性重度肥胖症在临床前期与心肌变形和扭转力学的变化有关，这些变化可能部分与心内膜下纤维的舒张和收缩特性的改变有关。
