异丙肾上腺素致心肌肥厚对兔心传导系统的影响

Effect of myocardial hypertrophy induced by isoproterenol on cardiac conduction system of rabbit in vivo.

目的通过对心肌肥厚兔模型进行电生理研究,探讨心肌肥厚对心传导系统的影响。方法雄性新西兰大耳兔24只,随机分为心肌肥厚组和对照组,每组各12只。经耳缘静脉注射异丙肾上腺素制备心肌肥厚模型。造模2周后行超声检查评价造模结果。对所有动物行在体电生理检查,测量两组动物心房有效不应期(AERP)、房室结有效不应期(AVERP)、房室结反向传导有效不应期(VAERP)、窦房传导时间(SACT)、最大窦房恢复时间(SNRTMAX)、文氏周期长度(WCL),反文氏周期长度(RWCL)、房室2∶1传导频率等指标。结果心肌肥厚组AERP较对照组缩短(68.60±6.20 ms vs 77.30±12.30 ms,P<0.05),SACT、SNRTMAX、AVERP、WCL及房室2:1传导频率较对照组延长(分别为101.57±25.11 ms vs 78.33±25.17 ms,616.91±59.89 ms vs 540.64±83.18 ms,160.30±9.73 ms vs 133.80±3.89 ms,191.40±32.90 ms vs 151.10±24.30 ms,148.8±35.00 ms vs 137.30±23.40 ms,P均<0.05),而VAERP与RWCL较对照组则无明显变化(P>0.05)。结论心肌肥厚可导致心传导系统功能受损,为心肌肥厚时心律失常的发生提供条件。

Objective To determine the effect of myocardial hypertrophy on cardiac conduction system by the electrophysiological study of rabbit in vivo.Methods Twenty-four male rabbits were equally randomly divided into two groups: control group and left ventricular hypertrophy(LVH) group.LVH was induced by injecting isoproterenol for 7 days.The animals developed LVH two weeks after injection.The atria effective refractory period(AERP),atrial-ventricular effective refractory period(AVERP),ventricular-atrial effective refractory period(VAERP),sinoatrial conduction time(SACT),sinus node recovery time(SNRT),WCL(Wenchebach cycle length),RWCL(Reserve-Wenchebach cycle length)and atrial-ventricular(A-V) 2∶1 conduction frequency were determined in both groups.Results Compared with control group,the AERP of LVH group was shortened(68.60±6.20 ms vs 77.30±12.30 ms,P<0.05),the SACT,SNRTMAX,AVERP,WCL and A-V 2∶1 conduction frequency were extended(101.57 ±25.11 ms vs 78.33±25.17 ms,616.91±59.89 ms vs 540.64 ± 83.18 ms,160.30±9.73 ms vs 133.80±3.89 ms,191.40± 32.90 ms vs 151.10±24.30 ms,148.80± 35.00 ms vs 137.30 ± 23.40 ms,all P<0.05),but the VAERP and RWCL had no change(P>0.05).Conclusion Myocardial hypertrophy injures the heart conduction system to benefit the arrhythmogenesis.