组织多普勒显像定量分析窦房结功能

目的 评价心动周期中窦房结内机械运动参数（如：加速度）的时空变化规律及其与心脏电兴奋之间的相关性。方法 制作5只犬开胸动物模型，用心内超声探头采集时间顺序窦房结组织多普勒图像，利用计算机图像处理与分析方法获取时间顺序窦房结内组织的加速度定量数据。结果 得到了窦房结兴奋过程中窦房结内心肌运动的加速度－时间曲线，其舒张末期初始加速度的起始时相与同步心电图特定时机（如：P波起始点）对照，二者具有很好的时相相关性。结论 由窦房结内组织多普勒顺序图像中得到的心肌兴奋的加速度－时间曲线及其与心电图时相之间的相关性，提示心内组织多普勒显像技术可用于定量评价窦房结内心肌机械兴奋及其与心肌电兴奋之间的关系。

Quantification of sinoatrial node function with tissue Doppler imaging

Objective To evaluate quantitatively electro mechanical function of sinoatrial node (SAN) with intracardiac ultrasonic tissue Doppler imaging.Methods It was that collected time sequence tissue Doppler images of SAN using an intracardiac ultrasonic catheter via superior vena cava, using the junction of anterior wall of superior vena cava and superior ridge of right atrial auricle as anatomic marks. It was that located the SAN region in the images with an ellipse crop box(the shape of the SAN region is like an ellipse in the images) and subdivide it into several regions.It was that separated the Doppler information (color signal) from the anatomical information (gray scale signal) and converted it to numerical values of acceleration automatically using dedicated software. The function parameters (i.e., the mean and variance of acceleration, the acceleration time curve, cumulative distribution function, etc.) at these regions separately was calculated.Results The three major waves on the acceleration time curve of SAN in one cardiac cycle were temporally related to specific simultaneous ECG phases (i.e., the first wave occurred at the very beginning of P wave, the second wave appeared during P R interval and the third wave started after QRS wave). The acceleration value and distribution were different among the total, inner and outer regions of SAN. The cumulative distribution function also provided an overview of the acceleration distribution within SAN at different phases.Conclusions The electro mechanical function of SAN could be evaluated quantitatively with time sequence intracardiac ultrasonic tissue Doppler images feasibly and practically. It may improve the understanding of the relationship between myocardial electro mechanical activation and anatomy within SAN, and conduce to SAN target pacing and precision ablation.