比格犬心室起搏状态左心室心肌三维位移的超声研究

Echocardiographic study of left ventricular 3-dimension displacement during different ventricular pacing in vivo：a canine model

目的 观察比格犬心室起搏状态左心室心肌三维峰值位移,量化评价心室不同起搏状态心肌力学状态特征,为优化心室起搏方式提供力学依据.方法 10只健康比格犬开胸模型,随机进行右心室心尖起搏（RVA-P）、左心室侧壁起搏（LVL-P）、左心室心尖起搏（LVA-P）,分别采集各种起搏状态一个完整心动周期的全容积实时灰阶图像.分析评价基础状态（BASE）及心室不同起搏状态左心室心肌三维峰值位移（3D-D）及其达峰时间（3D-DTC）和达峰时间标准差（3D-DTSD）.结果 ①LVL-P和LVA-P状态与BASE和RVA-P状态比较左心室的3D-D均有减低趋势,LVL-P与BASE、RVA-P状态比较左心室中前壁、中前间隔、中下壁、中后壁、中侧壁的3D-D差异有统计学意义（P＜0.05）;LVA-P与RVA-P状态比较左心室中前壁、中侧壁、中后壁的3D-D差异有统计学意义（P ＜0.05）;LVL-P和LVA-P状态与BASE和RVA-P状态比较左心室心尖水平各节段的3D-D差异有统计学意义（P＜0.05）.②LVL-P与BASE状态比较左心室底下壁、中下壁、尖下壁的3D-DTC差异有统计学意义（P＜0.05）;RVA-P、LVA-P状态与BASE状态比较左心室中侧壁的3D-DTC差异有统计学意义（P＜005）;心室不同起搏状态与BASE状态比较左心室3D-DTC均发生前移.③BASE与心室不同起搏状态比较左心窒3D-DTSD均无显著性差异,RVA-P和LVA-P状态比较左心室3D-DTSD差异有统计学意义（P＜0.05）.结论 RVA-P状态能够维持左心室心肌运动有效性和同步性;LVL-P和LVB-P状态均减低了正常左心室心肌三维运动的同步性,同时降低了左心室心尖和乳头肌水平节段心肌运动的有效性.通过对BASE及心室不同起搏状态左心室心肌三维状态的力学超声评价,有助于深入揭示更为真实的心室不同起搏状态左心室心肌力学异常.

Objective To evaluate the changes of left ventricular（LV） 3-dimension peak displacement （3D-D） during different cardiac pacing patterns. To provide a reliable mechanical data base for the optimization cardiac pacing. Methods Cardiac pacings in open-chest Beagle canine models（ n = 10） were performed using three patterns[I, e. , right ventricular apical pacing （RVA-P）, LV lateral pacing （LVL-P）and LV apical pacing（LVA-P）],3D full volumetric real-time imaging were acquired in a completed cardiac cycle. The 3D-D,3D-D peak time （3D-DTc） and the standard deviation of TC（3D-DTSD） were calculated and analyzed in different pacing patterns for difference and spatial correlationship. Results ① The 3D-D of LVL-P and LVA-P state decreased compared with BASE and RVA-P state, there were significant 3D-D difference of mid anterior,mid anteriorspetal, mid interior,mid posterior, mid lateral between LVL-P and BASE, RVA-P patterns（ P ＜0.05）. There were significant 3D-D difference of mid anterior,mid lateral,mid posterior between LVA-P and RVA-P patterns groups（ P ＜0.05）. There were significant 3D-D difference of all segments in apical level between LVL-P,LVA-P and BASE, RVA-P states（ P ＜0.05）. ② Corrected by the heart rate,the 3D-DTC of different cardiac pacing patterns were shorter than BASE state. ③ There were no significant 3D-DTSD difference between different cardiac pacings and BASE patterns. There were significant 3D-DTSD difference between RVA-P and LVA-P patterns （P ＜ 0.05）. Conclusions LV mechanical activation and synchronization could be maintained during RVA-P rather than LVA-P and LVL-P. Echocardiographic study of left ventricular 3D-D can actually reveal myocardial mechanical state during different cardiac pacings and BASE patterns.