起搏频率对主动脉跨瓣压力阶差影响的实验研究

The effect of pacing frequency on transaortic valve pressure gradients in goats

目的测量在不同起搏频率下主动脉跨瓣压力阶差的变化,为经导管主动脉瓣置入手术确定适合的起搏参数。方法选取6只成年健康山羊,全麻下经股静脉将临时起搏电极送至右心室,连接临时起搏器,频率范围由150次/分递增至350次/分,以25次/分递增频率,测量在不同起搏频率下主动脉瓣上和瓣下的收缩压、舒张压和平均压,并计算压力阶差。结果收缩期主动脉跨瓣压力阶差随起搏频率的加快而升高,至250~300次/分时,由（-25.00±3.90）mm Hg上升至（11.17±10.85）到（13.50±3.89）mm Hg之间。舒张期跨瓣压力阶差随起搏频率的加快而降低,至250~300次/分时,稳定在（47.00±3.03）mm Hg到（43.83±2.93）mm Hg之间,压力阶差降幅达50.11%。结论 250~300次/分的起搏频率可有效地降低主动脉跨瓣压力阶差,既能保证动物的安全又可减少因压力阶差引起的瓣膜置入过程中的移位。

Objective To study the changes of aotic transvalvular pressure gradient to determine the appropriate pacing frequency for transcatheter aortic valve implantation.Methods Six healthy adult goats were randomly chosen for the study were tested under general anesthesia.A temporary pacing lead connected with a temporary pacemaker was delivered to the right ventricle through the femoral vein.The pacing frequency range from 150 beats/min to 350 beats/min by increment of 25 beats/min.The aortic systolic,diastolic and mean pressure were measured at different pacing frequency and the pressure gradients in aortic were calculated.Results The transaortic valve systolic pressure gradient rose with the acceleration of the pacing rate.When the pacing rate accelerated to 250~300 beats/min,the pressure gradient rose from（-25.00±3.90） mm Hg to（11.17±10.85）-（13.50±3.89） mm Hg.Diastolic transvalvular systolic pressure gradient declined with the acceleration of the pacing rate.When the pacing rate accelerated to 250-300 beats/min,the pressure gradient was in the（43.83±2.93）-（47.00±3.03） mm Hg,showing a lower decline rate of 50.11%（P0.01,95% CI）.Conclusions The pacing rate at the range of 250 beats / min to 300 beats / min is appropriate to reduce transaortic valve pressure gradients during the transcatheter aortic valve implant procedure in goats.