Mihaila Sorina, Muraru Denisa, Miglioranza Marcelo Haertel, Piasentini Eleonora, Peluso Diletta, Cucchini Umberto, Iliceto Sabino, Vinereanu Dragos, Badano Luigi P
Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Via Giustiniani 2, 35128, Padua, Italy,
Int J Cardiovasc Imaging. 2015 Feb;31(2):279-90. doi: 10.1007/s10554-014-0547-0. Epub 2014 Oct 16.
Mitral annulus (MA) geometry and dynamics are crucial for preserving normal mitral valve (MV) function. Static reference values for MA parameters have been reported, but the normal MA dynamics during the entire cardiac cycle remains controversial. MV full-volume datasets were obtained by three-dimensional transthoracic echocardiography from 50 healthy volunteers (18-74 years; 31 men) to assess MA changes in size and shape during entire cardiac cycle. Using simultaneous multiplanar review, projected MA area (MAA) and circumference (MAC), antero-posterior (AP) and anterolateral-posteromedial (ALPM) diameters, and sphericity index (SphI) were obtained at: mitral valve closure (MVC), mid- and end-systole (ES), early- (EDF) and late-diastolic filling, and end-diastole. MAA and AP diameter were the most "active" parameters, changing in all reference frames (p < 0.001). MAA and AP diameter started to contract before MVC (during the left atrial contraction), reaching their minimum at MVC. Maximum MAA occurred at ES, while maximum AP diameter and SphI occurred at EDF. MAA fractional shortening was 35 ± 10 %. AP diameter change was 25 ± 10 %. MAC, ALPM and SphI showed similar patterns during left ventricular (LV) systole, and remained unchanged during diastole. Fractional change was 35 ± 10 % for MAC, and 13 ± 8 % for ALPM diameter. Our study provides the normal dynamics of the MA during the entire cardiac cycle. It reveals "pre-systolic" contraction of the MA, related to left atrial (LA) contraction, and minimal MAA during early LV systole. Therefore, the normal MA dynamics relates to a "physiologic LA-LV coupling", and a complete MA contraction requires both and properly timed LA and LV systole.
二尖瓣环（MA）的几何形状和动力学对于维持正常二尖瓣（MV）功能至关重要。已有关于MA参数的静态参考值报道，但整个心动周期中正常的MA动力学仍存在争议。通过三维经胸超声心动图从50名健康志愿者（年龄18 - 74岁；男性31名）获取MV全容积数据集，以评估整个心动周期中MA大小和形状的变化。使用同步多平面回顾，在二尖瓣关闭（MVC）、收缩中期和末期（ES）、舒张早期（EDF）和晚期充盈以及舒张末期获取投影MA面积（MAA）、周长（MAC）、前后径（AP）、前外侧 - 后内侧径（ALPM）和球形指数（SphI）。MAA和AP直径是最“活跃”的参数，在所有参考帧中均发生变化（p < 0.001）。MAA和AP直径在MVC之前（左心房收缩期间）开始收缩，在MVC时达到最小值。最大MAA出现在ES，而最大AP直径和SphI出现在EDF。MAA缩短率为35±10%。AP直径变化为25±10%。MAC、ALPM和SphI在左心室（LV）收缩期呈现相似模式，在舒张期保持不变。MAC的变化率为35±10%，ALPM直径的变化率为13±8%。我们的研究提供了整个心动周期中MA的正常动力学。它揭示了与左心房（LA）收缩相关的MA“收缩前期”收缩，以及左心室早期收缩时最小的MAA。因此，正常的MA动力学与“生理性LA - LV耦合”相关，并且完整的MA收缩需要适时的LA和LV收缩。
