磷酸二酯酶抑制剂(米力农)对左室功能和机械效率影响的研究

目的　利用压力 -容积关系分析磷酸二酯酶抑制剂 (米力农 )对左室收缩、舒张功能和机械效率的影响。方法　建立心内植入压力、容积测定装置的犬模型 ,利用压力 -容积关系 -评价左室功能的“金标准” ,系统分析自主神经阻滞前后米力农对左室舒缩功能和机械效率的影响。结果　阻滞自主神经前 ,米力农加快心率 (HR) ;使每搏容积 (SV)和射血分数 (EF)增加 ;使左室收缩末期压力 (PES) -收缩末期容积 (VES)、左室压最大上升速率 (dp/dtmax) -舒张末期容积 (VED)和心搏功 (SW) -VED三种关系位置左移 ,斜率增加 ,表明能够增强心肌收缩力 ;并提高左室舒张速率 (TC) ,加速左室舒张。米力农还能够使每搏功 (SW )、EES/Ea和SW /PVA值增加 ,改善左室与动脉系统的耦联 ,增强左室机械效率。阻滞自主神经后 ,这些变化仍然存在。结论　米力农可以增强心肌的收缩和舒张功能 ,提高左室机械作功效率。

Effects of Milrinone on left ventricular function and work efficiency:assessment by left ventricular pressure-volume analysis

Objective:To investigate the effects of milrinone on left ventricular (LV) function and work efficiency.Methods:we assessed the effect of milrinone (50μg/kg) on LV systolic performance、diastolic filling dynamics and work efficiency in 8 instrumented anesthetized dogs before and after autonomic blockade.Variably loaded pressure-volume loops were generated by transient caval occlusion.Results:With reflexes intact,Milrinone increased heart rate (HR)、eject fraction(EF) and the slopes of LV P ES-V ES relation,the dp/dtmax-V ED relation and the stroke work (SW)-V ED relation,shifted the three relations to the left,indicating milrinone caused a positive inotropic effect.Milrinone decreased the time constant of LV relaxation (T C),indicating the rate of LV relaxation was enhanced.Milrinone also increase the E ES/Ea ratio and the SW/PVA ratio.These effects preserved after autonomic blockade.Conclusion:Milrinone can augment LV contractile performance,accelerate LV relaxation,increase LV work efficiency and improve the coupling of LV and arterial system.