左心室辅助装置控制模式影响双心室搏动同步性的数值研究

Study on the synchronization of biventricular beats with the control mode of left ventricular assist device

右心室(RV)衰竭已成为左心室辅助装置(LVAD)治疗的一种致命并发症。由LVAD引起的双心室搏动的不同步是引发RV功能障碍的重要因素。本文采用数值方法研究LVAD的控制模式对左、右心室搏动同步性的影响。数值结果表明:左心室(LV)与RV的收缩持续时间在无泵模式下没有显著差异(分别为48.52%和51.77%)。连续模式下,LV收缩期明显短于RV收缩期(LV vs.RV:24.38%vs.49.16%)和无泵模式的LV收缩期。搏动模式下,LV收缩期明显短于RV收缩期(LV vs.RV:28.38%vs.50.41%)但长于连续模式的LV收缩期。反搏动模式中的LV、RV收缩期差异较小(LV vs.RV:43.13%vs.49.23%),而LV收缩期短于无泵模式,并且长于连续模式。与连续和搏动模式相比,由反搏动模式提供的收缩期转速(RS)降低显著地校正了LV收缩持续时间,连续模式下缩短的收缩持续时间在反搏动模式下被校正为LV和RV之间的重新同步。因此,本文认为LV和RV收缩的再同步有助于预防RV功能障碍。总之,使用在收缩期间降低RS的反搏动模式有望用于由LVAD引起的双心室搏动不同步的临床校正。

Right ventricular(RV)failure has become a deadly complication of left ventricular assist device(LVAD)implantation,for which desynchrony in bi-ventricular pulse resulting from a LVAD is among the important factor.This paper investigated how different control modes affect the synchronization of pulse between LV(left ventricular)and RV by numerical method.The numerical results showed that the systolic duration between LV and RV did not significantly differ at baseline(LVAD off and cannula clamped)(48.52%vs.51.77%,respectively).The systolic period was significantly shorter than the RV systolic period in the continuous-flow mode(LV vs.RV:24.38%vs.49.16%)and the LV systolic period at baseline.The LV systolic duration was significantly shorter than the RV systolic duration in the pulse mode(LV vs.RV:28.38%vs.50.41%),but longer than the LV systolic duration in the continuous-flow mode.There was no significant difference between the LV and RV systolic periods in the counter-pulse mode(LV vs.RV:43.13%vs.49.23%).However,the LV systolic periods was shorter than the no-pump mode and much longer than the continuousflow mode.Compared with continuous-flow and pulse mode,the reduction in rotational speed(RS)brought out by counter-pulse mode significantly corrected the duration of LV systolic phase.The shortened duration of systolic phase in the continuous-flow mode was corrected as re-synchronization in the counter-pulse mode between LV and RV.Hence,we postulated that the beneficial effects on RV function were due to re-synchronizing of RV and LV contraction.In conclusion,decreased RS delivered during the systolic phase using the counter-pulse mode holds promise for the clinical correction of desynchrony in bi-ventricular pulse resulting from a LVAD and confers a benefit on RV function.