左心室重构导致心肌做功分布均匀化。
Left Ventricular Remodeling Results in Homogenization of Myocardial Work Distribution.
机构信息
Department of Cardiovascular Sciences (J.D., S.Ü., E.D.P., S.B., M.C., P.C., F.R., J.-U.V.), KU Leuven, Belgium.
Department of Cardiovascular Diseases (J.D., S.Ü., E.D.P., S.B., M.C., J.-U.V.), University Hospitals Leuven, Belgium.
出版信息
Circ Arrhythm Electrophysiol. 2019 May;12(5):e007224. doi: 10.1161/CIRCEP.118.007224.
BACKGROUND
The interaction between regional left ventricular (LV) myocardial work and metabolism in remodeled hearts has not yet been well established. Our aim was to investigate the effect of inhomogeneous LV work distribution on regional metabolism and remodeling in our animal model with reversible dyssynchrony due to pacing.
METHODS
In 12 sheep, 8 weeks of right atrial and right ventricular free wall (DDD) pacing lead to LV dilatation, a thinned septum, and thickened lateral wall. Left bundle branch block-like dyssynchrony caused by DDD pacing could be acutely reverted by right atrial pacing (AAI) only. Invasive hemodynamics and echocardiography were used to assess regional work by stress-strain loop area and compared with regional glucose metabolism measured by F-fluorodeoxyglucose positron emission tomography with and without improved spatial resolution by motion and anatomy correction on gated reconstructions.
RESULTS
Glucose metabolism by positron emission tomography with anatomic correction on gated positron emission tomography reconstruction showed a different regional distribution than with clinical reconstructions and correlated best and significantly with regional myocardial work. At baseline, work was homogeneously distributed with normal conduction (AAI pacing), whereas during dyssynchrony (DDD pacing), the lateral wall was more loaded, and the septum was unloaded. After 8 weeks of remodeling under DDD pacing, however, an almost homogeneous work distribution was found with DDD pacing, whereas with AAI pacing, the thin septum showed exaggerated loading and the lateral walls a low load. Our experimental observations were confirmed in 5 patient responders to cardiac resynchronization therapy.
CONCLUSIONS
Regional LV glucose metabolism closely correlates with regional work. Our data indicate that regionally different LV remodeling after exposure to inhomogeneous loading conditions, such as during LV dyssynchrony, is an adaptive process that helps to equilibrate work distribution. Correction of the inhomogeneous loading conditions, such as during cardiac resynchronization therapy, then triggers a reverse LV remodeling through the same mechanism.
背景
区域性左心室（LV）心肌做功与代谢之间的相互作用尚未得到很好的证实。我们的目的是通过使用右心房和右心室游离壁起搏（DDD）建立的可逆转失同步动物模型来研究 LV 工作分布不均匀对区域性代谢和重构的影响。
方法
在 12 只绵羊中，8 周的右心房和右心室游离壁起搏（DDD）导致 LV 扩张、室间隔变薄和侧壁增厚。DDD 起搏引起的左束支传导阻滞样失同步可以通过仅右心房起搏（AAI）来急性逆转。采用压力-应变环面积评估区域做功的侵入性血流动力学和超声心动图，并与正电子发射断层扫描（PET）测量的 F-氟脱氧葡萄糖代谢进行比较，通过门控重建时运动和解剖校正来提高空间分辨率。
结果
门控 PET 重建时解剖校正的 PET 显示葡萄糖代谢的区域性分布与临床重建不同，与局部心肌做功相关性最好且显著相关。在正常传导（AAI 起搏）时，基线工作均匀分布，而在失同步（DDD 起搏）时，侧壁负荷增加，室间隔卸载。然而，在 DDD 起搏下 8 周重构后，发现 DDD 起搏时几乎呈均匀工作分布，而 AAI 起搏时，薄的室间隔表现出明显的负荷过重，而侧壁的负荷较低。我们的实验观察结果在 5 例对心脏再同步治疗有反应的患者中得到了证实。
结论
区域性 LV 葡萄糖代谢与区域性做功密切相关。我们的数据表明，暴露于不均匀负荷条件下（如 LV 失同步）后，区域性 LV 重构是一种适应性过程，有助于平衡做功分布。不均匀加载条件的校正，如心脏再同步治疗，通过相同的机制触发 LV 重构的逆转。
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