改变在体兔左心室后负荷对其电生理参数的影响

目的：探讨改变在体兔左心室后负荷对室性心律失常发生情况及左心室电生理参数的影响。方法：改变左心室后负荷，观察室性心律失常发生情况，并测定左心室舒张阈值（ＶＤＴ），相对不应期（ＲＲＰ），有效不应期（ＥＲＰ）及其不应期离散和心室纤颤阈（ＶＦＴ）。结果：逐级增加左心室后负荷（ＡＢ级）可使左室空间ＲＲＰ，ＥＲＰ离散增加（Ｂ级，Ｐ＜００５），ＶＦＴ降低（Ｂ级，Ｐ＜００１）；各实验动物均出现室性心律失常（Ｂ级）；而逐级减小左室后负荷（ＣＤ级），心室电生理参数无变化（Ｐ＞００５），各实验动物亦无室性心律失常发生。结论：增加左心室后负荷诱发室性心律失常，与左室空间不应期离散增加有关。

Effect of changing left ventricular afterload of rabbit heart on its electrophysiological parameters

AIM:To study the effects of alteration of left ventricular afterload of rabbit heart on occurrence of ventricular arrhythima and left ventricular electrophysiologic parameters.METHODS:Changing afterload of left ventricle (LV), occurrence of ventricular arrhythmia, left ventricular diastolic thresholds (VDT), relative refractory period (RRP), effective refractory period (ERP), dispersion of refractory period, and ventricular fibrillation threshold (VFT) were recorded.RESULTS:Increasing afterload in LV step by step(grade A and B) caused increase of temporal dispersion of left ventricular relative and effective refractory period [(RRP and ERP),gradeB, P <0 05] and decrease of ventricular fibrillation threshold [(VFT), gradeB, P <0 01]. In all animals, ventricular arrhythmia occured. But reducing left ventricular afterload step by step (grade C and D)did not alter the electrophy siological parameters in LV( P >0 05) and did not induce ventricular arrythmia.CONCLUSION:Ventricular arrhythmia induced by increasing afterload in LV related to increase of temporal dispersion of refractory period.