快速右室起搏致充血性心力衰竭犬心室复极离散性的变化

目的研究快速右室起搏致充血性心力衰竭(CHF)犬心室复极离散性的变化。方法25只犬随机分成两组:对照组(n=10)及CHF组(n=15)。应用快速右室起搏(240次/分,共4～5周)制作CHF犬模型,应用心脏电刺激技术测定心电生理参数。结果与对照组比较,CHF组左右室的心室兴奋恢复时间(VRT)均明显延长(P<0.01),心尖部的VRT延长更明显(P<0.05),VRT离散性(DVRT)明显增加(32±6msvs13±4ms,P<0.01);左室三层心肌VRT均明显延长(P<0.01),中层心肌的VRT延长更明显(P<0.05),跨室壁DVRT(TDVRT)明显增加(44±8msvs19±5ms,P<0.01);CHF组心室颤动阈值(VFT)明显降低(11±3mAvs34±7mA,P<0.01)。结论CHF犬DVRT及TDVRT明显增大,使心室复极不均一,易致折返活动,同时VFT降低。

Dispersion of ventricular repolarization in a right ventricular rapid pacing-induced canine congestive heart failure model

Objective To investigate the change of dispersion of ventricular repolarization in a right ventricular rapid pacing-induced canine congestive heart failure(CHF) model in vivo.Methods Dogs(n=25) were randomized into two groups:group 1(n=10) was the control.Dogs in group 2(n=15) were the CHF models induced by right ventricular rapid pacing(240 bpm for 4 to 5 weeks).The ventricular electrophysiological variables were evaluated by standard electric stimulation protocol.Results The ventricular recovery time(VRT) of left and right ventricles prolonged obviously(P<0.01)with more obvious prolongation of VRT in the apex(P<0.05)and dispersion of VRT(DVRT) increased obviously(32±6 ms vs 13±4 ms,P<0.01)in CHF group.The VRT of the three layers of myocardium in left ventricle prolonged obviously in CHF group(P<0.01) with more obvious prolongation of VRT in midmyocardium(P<0.05) and transmural DVRT(TDVRT) increased obviously(44±8 ms vs 19±5 ms,P<0.01).Ventricular fibrillation threshold(VFT) decreased in CHF group(11±3 mA vs 34±7 mA,P<0.01).Conclusions DVRT and TDVRT increase with VFT decreasing in CHF dogs.