心房颤动患者左心房自发超声显影的超声学和方法学研究

Echocardiographic and methodological study on left atrial spontaneous echo contrast in patients with atrial fibrillation

目的 探讨心房颤动（房颤）患者左心房自发超声显影（SEC）的超声学机制。方法经胸或经食管超声心动图分别测定44例房颤患者左心功能、形态学参数、左心耳和左上肺静脉血流速度，背向散射积分定量测量左心房SEC，共线性分析筛选独立的血流速度参数，后者与显著性形态学指标行多因素分析。结果 与左心房SEC显著性相关的有左心房内径、左心耳入口内径、左心耳排空／充盈血流速度峰值、积分（Vi）和充盈血流速度平均值（RVm）、左上肺静脉血流速度S／D波峰值、S波积分（PVS-VTI）和D波平均值（PVD-M）（P〈0．05-0．01）。共线性分析显示，RVm、RVi、PVS-VTI和PVD-M为独立、代表性血流速度指标。多因素分析显示，RVm和PVD-M为左心房SEC的独立预测因子（P〈0．05）。结论 左心耳充盈顺应性降低和跨二尖瓣血流的阻挡为左心房SEC形成的主要超声学机制，共线性分析为研究血流动力学和左心房SEC之间相互关系的有效方法。

Objective To investigate the independent echocardiographic pathogenesis associated with left atrial spontaneous echo contrast（SEC） formation in patients with atrial fibrillation（AF）. Methods Twenty-one patients with valvular AF and twenty-three patients with nonvalvular AF undergoing transthoracic and transesophageal echocardiography （TTE/TEE） were studied. Morphological and functional parameters of the heart in patients with AF were detected by TTE, while the sizes of the left atrial appendage（LAA）, its Doppler flow patterns,Doppler flow patterns of the left upper pulmonary vein and integrated backscatter（IBS） values of left atrial SEC relative to those of the left ventricle were measured by TEE. Results There were the following 10 variables significantly associated with the left atrial SEC, some of which associated positively with SEC were left atrial diameter（ r = 0, 40252, P = 0. 0061） ,diameter of the open mouth of LAA to the left atrium（ r = 0. 37816, P = 0. 0161）, while the others of which associated negatively with SEC were antegrade/retrograde blood flow velocity peak,integrate （RVi） and retrograde blood flow velocity mean（RVm） values,and S/D wave peak,S wave integrate（Is） and D wave mean（Md） values, their r values ranged from - 0. 40379 to - 0. 32832, their P values between 0. 0018 and 0. 0386. Collinearity analyses suggested that RVi, RVm, Is, Md represented completely all the blood flow velocity parameters of LAA and the left upper pulmonary vein, respectively. Multivariate analyses demonstrated that RVm and Md were the independent predictors of the left atrial SEC in patients with AF （ both P〈0. 05）. Conclusions The lowering compliance of LAA and different transmitral obstructions are the main echocardiographic pathogenesis of the left atrial SEC formation, while collinearirty analysis is a new and effective statistical method used to study the association of left atrial SEC formation with hemodynamics in patients with AF.