心力衰竭犬心房电生理特性的研究

为观察心力衰竭 (简称心衰 )犬心房肌电生理特性的改变 ,探讨充血性心衰时心房颤动 (AF)发生机制。选择14只犬随机分为起搏组 (n =7)和假手术组 (n =7) ,在左、右房各缝植 4对电极 ,电极尾端经皮下由犬背部穿出。假手术组犬埋置起搏器后不起搏。起搏组犬置入实验用VOO型起搏器快速心室起搏 (2 2 0次 /分 ) 6周 ,建立心衰犬模型 ,分别于起搏前、起搏 6周后 ,测定心房有效不应期 (AERP)、AERP离散度 (AERPd)、房内和房间传导时间及心房肌传导速度 ,记录AF诱发情况。结果 :①假手术组犬术前与术后比较 ,心功能和心房电生理特性均无明显变化。②心室快速起搏 6周犬AERP较起搏前略延长 ,但差异无显著性。起搏 6周犬AERPd较起搏前明显增大 (4 0 .4±15 .6msvs 2 2 .6± 10 .2ms,P <0 .0 5 )。与起搏前比较 ,起搏 6周犬房内及房间传导时间明显延长 (CTRA5 4 .7± 7.2msvs 33.1± 9.5ms ;CTLA5 2 .3± 8.9msvs 31.7± 6 .3ms ;CTRA LA6 9.7± 8.2msvs 4 2 .8± 7.9ms,P均 <0 .0 5 ) ,心房肌传导速度显著减慢 (CVRA5 4 .8± 7.9cm/svs 90 .7± 8.4cm/s ;CVLA5 7.4± 9.6cm/svs 94 .6± 10 .2cm/s,P均 <0 .0 5 )。③心衰犬AF诱发率、诱发次数、AF持续时间较起搏前明显增加。假手术组犬术前、术后比较AF诱发情况无?

The Study of Atrial Electrophysiological Characteristics in Canine Congestive Heart Failure

To observe the atrial electrophysiological characteristics in canine congestive heart failure induced by chronic rapid ventricule pacing and investigate the mechanism of atrial fibrillation(AF) in congestive heart failure. 14 canines were randomly divided into sham-operated group(n=7) and ventricule pacing group(n=7). Four pairs electrodes were sutured to four sites in each atrium. A pacemaker (VOO) was implanted in a subcutaneous pocket and attach to a screw-in epicardial lead in the apex of right ventricule. The dogs in ventricule pacing group were paced at 220 bpm for 6 weeks. Before and after 6-week rapid ventricule pacing, atrial effective refrectory period(AERP)in four sites,AERP dispersion(AERPd),intra-atrium conduction velocity, intra-atrium and inter-atrium conduction time, inducibility and duration of AF were measured.Results: ①There were no changes of cardiac function and atrial electrophysiological characteristics before and after the procedure in sham-operated group. ②After rapid ventricule pacing for 6 weeks, AERP prolonged slightly in congestive heart failure canines. AERPd increased significantly after rapid ventricule pacing for 6 weeks(40.4±15.6 ms vs 22.6±10.2 ms,P<0.05).Inter-atrium conduction time and intra-atrium conduction time prolonged significantly in congestive heart failure canines. After rapid ventricule pacing inter-atrium conduction velocity slower than before.③Frequency and duration of AF were obviously increased in congestive heart failure canines but no changes in sham-operated group. Conclusion: Inter-atrium and intra-atrium conduction abnormalities and increased AERPd may play an important role in the electrophysiologic substrate for AF in congestive heart failure .