Itabashi Yuji, Mihara Hirotsugu, Berdejo Javier, Utsunomiya Hiroto, Shiota Takahiro
Noninvasive Cardiac Laboratory, Cedars-Sinai Heart Institute, Los Angeles, CA, USA.
Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
J Heart Valve Dis. 2016 May;25(3):323-331.
The study aim was to investigate the mechanism of mitral regurgitation (MR) in lone atrial fibrillation (AF) patients using three-dimensional (3D) transesophageal echocardiography (TEE).
A retrospective analysis was conducted of 64 patients with AF and a normal left ventricle, and without prolapse of the mitral valve. Among these patients, significant MR was not identified in 33 cases (AF+MR- group) but was present in 31 cases (AF+MR+ group). The distance from the coaptation to the bending point of the anterior mitral leaflet (AML), where the chorda was attached, was termed the 'bending length'. The ratio of the bending length to the distance from coaptation to anterior mitral annulus was termed the 'bending ratio' (= bending length/coaptation-annulus length). The mitral annular area (MAA) fractional change was defined as follows: (MAA at late systole - MAA at early systole)/MAA at late systole × 100%). Other parameters relating to mitral valve morphology obtained using 3D TEE were measured with commercial software (QLAB, Phillips).
The coaptation length (CL) was smaller in the AF+MR+ group than in the AF+MR- group (p<0.001), and correlated significantly with the anteriorposterior diameter of the mitral annulus (R = 0.286, p = -0.022), MAA at mid-systole (R = -0.269, p = 0.032), MAA fractional change (R = 0.434, p <0.001), and the bending ratio (R = -0.603, p <0.001). With a multivariable analysis, the correlating factors of significant MR in lone AF patients were a decrease in MAA fractional change (p = 0.022) and an increase of the bending ratio (p = 0.009).
Small MAA fractional changes and the distant position of the chordae tendineae on the AML from the coaptation correlated with significant MR in AF patients with normal left ventricular systolic function.
本研究旨在利用三维（3D）经食管超声心动图（TEE）探究孤立性心房颤动（AF）患者二尖瓣反流（MR）的机制。
对64例左心室正常且无二尖瓣脱垂的AF患者进行回顾性分析。在这些患者中，33例未发现显著MR（AF+MR-组），31例存在显著MR（AF+MR+组）。二尖瓣前叶（AML）腱索附着处的瓣叶贴合点至弯曲点的距离称为“弯曲长度”。弯曲长度与瓣叶贴合点至二尖瓣前瓣环距离的比值称为“弯曲率”（=弯曲长度/瓣叶贴合-瓣环长度）。二尖瓣环面积（MAA）分数变化定义如下：（收缩期末期MAA - 收缩期初期MAA）/收缩期末期MAA×100%）。使用3D TEE获得的与二尖瓣形态相关的其他参数通过商业软件（QLAB，飞利浦）进行测量。
AF+MR+组的瓣叶贴合长度（CL）小于AF+MR-组（p<0.001），且与二尖瓣环前后径显著相关（R = 0.286，p = -0.022）、收缩中期MAA（R = -0.269，p = 0.032）、MAA分数变化（R = 0.434，p <0.001）以及弯曲率（R = -0.603，p <0.001）。多变量分析显示，孤立性AF患者显著MR的相关因素为MAA分数变化降低（p = 0.022）和弯曲率增加（p = 0.009）。
左心室收缩功能正常的AF患者中，较小的MAA分数变化以及AML上腱索离瓣叶贴合点较远的位置与显著MR相关。
