异丙肾上腺素致心肌肥厚对兔心传导系统的影响

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。

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

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.