牵张预适应对牵张体外大鼠左心室致心律失常的影响

Effect of stretch preconditioning on stretch-inducedly ventricular arrhythmias in isolated rat hearts

目的:研究牵张预适应对牵张体外大鼠左心室致心律失常的影响。方法:采用膨胀球囊牵张Langendorff方法灌流的体外大鼠心脏模型,观察牵张之前和过程中的心电图、左室压力的变化。结果:机械扩大左心室引起室性心律失常及短暂的时间依赖性的机械———电适应期,适应期内进行第2次牵张,由此引起的心律失常减少或消失。牵张预适应依赖于两次牵张的间期。第2次牵张引起的室性心律失常随球囊膨胀体积的增加而增多。0.6g/L链霉素(一种非特异牵张激活离子通道阻滞剂)可以部分抑制膨胀致心律失常。结论:牵张预适应具有时间依赖性的抗牵张致心律失常的作用,可能为临床上心律失常治疗提供新的思路。

Objective:To study stretch preconditioning on stretch-inducedly ventricular arrhythmia by inflation of latex ballon in the ventricular of isolated rat heart.Method:The isolated rat hearts perfused by the Langendorff technique were used. Balloon inflation in the left ventricular of isolated heart to increase the left ventricular preload dilated the left ventricular and produced premature ventricular beats. We recorded the change of ECG's and pressure of left ventricular before and during mechanical intervention.Result:The study showed that mechanical intervention can be arrhythmogenic and induce a time-dependent mechanoelectic adaptation period during which stretch-induced arrhythmia disappeared or decreased on a subsequent stretch. The anti-arrhythmic effect depended on the period between the first mechanical intervention and the subsequent one. The probability of eliciting a stretch-induced arrhythmia increased when increasing the amplitude of the second dilation. 0.6 g/L streptomycin can partly inhibit the stretch-induced arrhythmias.Conclusion:Transient ventricular stretch produces premature ventricular beats and is transiently anti-arrhythmic against a subsequent mechanically induced arrhythmia. The anti-arrhythmic effect is weakened when the subsequent stretch increases. The induction of a myocardium mechanoelectic adaptation period will possibly provide a new way for treating clinical arrhythmias.