缝隙连接对心肌肥厚兔室性心律失常的影响

目的研究兔慢性压力超负荷模型中缝隙连接(G J)对室性心律失常的影响。方法30只兔随机分为假手术组(Sham组)、心肌肥厚组(LVH组)和抗心律失常肽组(AAP10组)。LVH组和AAP10组通过缩窄腹主动脉制备兔左室压力超负荷心肌肥厚模型,Sham组仅游离腹主动脉未进行缩窄。动物饲养3个月后制备兔左室楔形心肌块的灌注模型,Sham组和LVH组灌流台氏液,AAP10组灌流含AAP10的台氏液,记录不同起搏周长下容积心电图、跨室壁离散度(TDR)及刺激反应间期(SR I),并观察早期后除极(EAD)及室性心律失常的发生率。结果在不同频率起搏下,LVH组SR I和TDR与Sham组比较均明显增加(P<0.05)。而AAP10组的SR I和TDR与LVH组比较明显减小(P<0.05)。Sham组无1例诱发EAD和室性心律失常;在5 000 m s起搏时LVH组和AAP10组EAD的发生率分别为10/10、3/10,室性心律失常发生率分别为4/10,1/10,两组比较差异有显著性(P<0.05)。结论G J激动剂AAP10减轻了心肌肥厚时SR I的延长和TDR增加,相应的减少了EAD和室性心律失常的发生率。

Effects of gap junction on ventricular arrhythmias in hypertrophic myocardium of rabbit

Objective To explore the effects of gap junction(GJ) on ventricular arrhythmias in left ventricular hypertrophy(LVH).Methods Thirty rabbits were randomly divided into three groups: Sham group,LVH group and AAP10 group.In LVH group and AAP10 group,the abdominal aorta was partially constricted.In Sham group,the abdominal aorta was only exposed without constriction.The arterially perfused left ventricular wedge preparations were made after three months.The wedge preparations were perfused with Tyrode′s solution in Sham group and LVH group,and with Tyrode′s solution containing AAP10 in AAP10 group.Volume electrocardiogram,stimulus response interval(SRI),transmural repolarization dispersion(TDR) and the incidences of early afterdepolarization(EAD) and ventricle arrhythmias at different cycle lengths were recorded.Results At different cycle lengths,TDR and SRI in LVH group significantly increased compared with those in Sham group(P<0.05).TDR and SRI significantly decreased in AAP10 group compared with those in LVH group(P<0.05).EAD and ventricular arrhythmias were not induced in Sham group.At 5000ms cycle lengths the incidences of EAD in LVH group and AAP10 group were 10/10,3/10 respectively,and the incidences of ventricular arrhythmias in LVH group and AAP10 group were 4/10,1/10,respectively.There was significant difference in the incidences of EAD and ventricular arrhythmias between LVH group and AAP10 group(P<0.05).Conclusions AAP10 can short SRI and reduce TDR in ventricular hypertrophy and result in lower incidences of EAD and ventricular arrhythmias.