实时三维超声心动图对二尖瓣环形态的实验研究

Investigation of mitral annular geometry using real-time three-dimensional echocardiography

目的探讨实时三维超声心动图(RT-3DE)研究二尖瓣环立体形态的方法和可行性。方法采用RT-3DE获取8只犬冠状动脉左回旋支结扎前和结扎后心脏三维全容积图像,然后于舒张末期对二尖瓣环进行标记,测量二尖瓣环投影面积,观察二尖瓣环的立体形态及其在冠状动脉左回旋支结扎前后的变化。结果通过对二尖瓣环标记,显示二尖瓣环呈“马鞍形”的立体形态;冠状动脉左回旋支结扎后,二尖瓣环发生非对称性扩张,扩张部位主要位于后部瓣环近后内侧连合处,二尖瓣环面积结扎前(17.7±4.6)cm2,结扎后(24.5±7.1)cm2(P<0.05),增加百分比为(31.9±5.6)%,二尖瓣环仍呈“马鞍形”,但形态较结扎前平坦。结论可以采用RT-3DE无创伤性研究不同病理生理状态下二尖瓣环的立体形态,这将有助于深入探讨功能性二尖瓣反流的形成机制。

Objective To investigate The method and feasibility of analysing mitral annulus geometry via real-time three-dimensional echocardiography (RT-3DE). Methods The full-volume image was acquired on RT-3DE both at baseline and after left circumflex (LCX) artery occlusion in 8 canines. Then mitral annulus was marked. The mitral annular projective area was measured. The mitral annular configuration was also observed and was compared at the baseline and after LCX occlusion. Results 1. Mitral annulus was showed “stero-saddle” shape after being marked. 2. After LCX occlusion, mitral annulus asymmetrically dilated mainly in posterior portion, near posterior commissure, with area increased by 31.9±5.6% (P<0.05), and the mitral annulus became flatter after LCX occlusion than at the baseline. Conclusions Real-time three-dimensional echocardiography may be used as a non-invasive method to investigate the configuration of mitral annulus at different pathophysiologic status. It may give a hand to investigate the main mechanism of functional mitral regurgitation.