斑点追踪显像技术评价起搏器植入术后左心室扭转

目的 应用斑点追踪显像(speckle tracking imaging,STI)技术评价右心室不同部位起搏后左心室扭转变化,揭示心室激动顺序异常时左室心肌扭转的变化.方法 选择11例右室心尖(right ventricular apex,RVA)起搏患者,11例右室流出道(right ventricular outflow tract,RVOT)起搏患者及13例正常志愿者,应用STI技术对其胸骨旁左室心尖和基底段短轴的二维图像分析左室心肌的旋转.结果 ①起搏组的扭转曲线普遍较正常对照组降低、顿挫,RVA起搏组(12.57°±4.19°)、RVOT起搏组(12.43°±5.46°)的扭转角度峰值均小于正常对照组(18.98°±5.73°),差异有统计学意义(均P＜0.01),而两起搏组间比较差异无统计学意义(P＞0.05),扭转角度达峰时问在三组间两两比较差异无统计学意义(P＞0.05).②心尖段扭转角度在正常对照组、RVA起搏组及RVOT起搏组中呈现递减趋势,但仅RVOT起搏组与正常对照组问差异有统计学意义(7.40°±4.27°对12.70°±6.82°,P=0.0364).③基底段扭转角度达峰时间标准差(Tp-SD)比较,RVOT起搏组显著大于正常对照组(14.1%对4.87%,P=0.0298);而整体Tp-SD比较,RVA起搏组显著大于正常对照组(7.6±6.5)%对2.26(1.62～3.51)%,P=0.0423].④与正常对照组相比,起搏组的扭转速度曲线较杂乱无序,但三组间两两比较扭转速度峰值、解旋速度峰值、扭转速度达峰时间、解旋速度达峰时间差异均无统计学意义.结论 起搏器植入后心肌节段扭转同步性降低,左室整体扭转受到抑制,可能影响左室收缩功能和舒张功能.

Evaluating left ventricular torsion of different right ventricular pacing sites by speckle tracking imaging

Objective To evaluate the left ventricular(LV)torsion in patients with permanent pacemaker implantation by speckle tracking imaging(STI).Methods Twenty-two patients with permanent pacemaker implantation were enrolled.Eleven of them had the pacing electrodes placed in the right ventricular(RV)apex(RVA group)and the others had the pacing electrodes placed in the RV outflow tract (RVOT group).Thirteen healthy subjects were studied as controls.The basal and apical shortaxis views of the left ventricle were acquired and analyzed using EchoPAC 7.0 station.Results ①The curves of LV torsion in the pacing groups were generally lower than those in the control group and notched.The torsion parameters of RVA group and RVOT group were all less than those of control group(Ptw:12.57±4.19°vs 12.43±5.46°vs 18.98±5.73°,all P＜0.05),but there were no significant differences between RVA group and RVOT group.The time of torsion was not changed in the pacing groups because there were no significant differences among the three groups.②The values of Ptw-a(peak twist of the apex)were gradually declined among control group,RVA group and RVOT group.There was statistical difference in Ptw-a between RVOT group and control group(7.40±4.27°vs 12.70±6.82°,P=0.0364).③The basal Tp-SD(standard deviation of times to peak twist)of RVOT group was significantly longer than that of control group14.1(7.97～22.70)%vs 4.87(3.03～7.79)%,P=0.0298].And total Tp-SD of RVA group was significantly longer than that of control group(7.6±6.5)%vs 2.26(1.62～3.51)%,P=0.0423].④The curves of torsion velocity in the pacing groups were obviously disorganized compared with control group.But there were no statistical differences in Ptv(peak twist velocity),Putv(peak untwisting velocity),Tptv(time to peak twist velocity)and Tutv(time to peak untwisting velocity)among the three groups.Conclusions The RV pacing tends to impair torsional synehrony of LV and depress LV torsion,though it doesn't change the timing of LV torsion.It may impair LV systolic and diastolic function.