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

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

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。

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 midmyoc ardium（ 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.