Pedrizzetti Gianni, Martiniello Alfonso R, Bianchi Valter, D'Onofrio Antonio, Caso Pio, Tonti Giovanni
Department of Engineering and Architecture, University of Trieste, P.le Europa 1., Trieste 34127, Italy
Department of Cardiology, Monaldi Hospital, AORN Ospedali dei Colli, Napoli, Italy.
Eur Heart J Cardiovasc Imaging. 2016 Feb;17(2):203-9. doi: 10.1093/ehjci/jev137. Epub 2015 Jun 9.
Changes in electrical activation sequence are known to affect the timing of cardiac mechanical events. We aim to demonstrate that these also modify global properties of the intraventricular blood flow pattern. We also explore whether such global changes present a relationship with clinical outcome.
We investigated 30 heart failure patients followed up after cardiac resynchronization therapy (CRT). All subjects underwent echocardiography before implant and at follow-up after 6+ months. Left ventricular mechanics was investigated at follow-up during active CRT and was repeated after a temporary interruption <5 min later. Strain analysis, performed by speckle tracking, was used to assess the entity of contraction (global longitudinal strain) and its synchronicity (standard deviation of time to peak of radial strain). Intraventricular fluid dynamics, by echographic particle image velocimetry, was used to evaluate the directional distribution of global momentum associated with blood motion. The discontinuation of CRT pacing reflects into a reduction of deformation synchrony and into the deviation of blood flow momentum from the base-apex orientation with the development of transversal flow-mediated haemodynamic forces. The deviation of flow momentum presents a significant correlation with the degree of volumetric reduction after CRT.
Changes in electrical activation alter the orientation of blood flow momentum. The long-term CRT outcome correlates with the degree of re-alignment of haemodynamic forces. These preliminary results suggest that flow orientation could be used for optimizing the biventricular pacing setting. However, larger prospective studies are needed to confirm this hypothesis.
已知电激活序列的变化会影响心脏机械事件的发生时间。我们旨在证明这些变化也会改变心室内血流模式的整体特性。我们还探讨这种整体变化是否与临床结果存在关联。
我们对30例接受心脏再同步治疗（CRT）后的心力衰竭患者进行了随访。所有受试者在植入前及6个月以上的随访时均接受了超声心动图检查。在随访期间，于CRT激活状态下对左心室力学进行研究，并在<5分钟后的临时中断后重复进行。通过斑点追踪进行应变分析，以评估收缩的程度（整体纵向应变）及其同步性（径向应变峰值时间的标准差）。通过超声粒子图像测速技术评估心室内流体动力学，以评估与血液流动相关的整体动量的方向分布。CRT起搏的中断反映为变形同步性降低，以及随着横向血流介导的血流动力学力的发展，血流动量从心底 - 心尖方向发生偏移。血流动量的偏移与CRT后容积减少的程度呈显著相关。
电激活的变化会改变血流动量的方向。长期CRT结果与血流动力学力重新排列的程度相关。这些初步结果表明，血流方向可用于优化双心室起搏设置。然而，需要更大规模的前瞻性研究来证实这一假设。
