卡维地洛对扩张型心肌病跨室壁复极不均一性的影响

Effect of Carvedilol on Transmural Heterogeneity of Ventricular Repolarization in Rabbit Models of Dilated Cardiomyopathy.

为观察卡维地洛对扩张型心肌病跨室壁复极不均一性的作用,将24只家兔随机分为扩张型心肌病组、卡维地洛组和正常对照组。阿霉素静脉注射8周造成扩张型心肌病模型,卡维地洛组给予口服卡维地洛8周进行干预。在体用非程序刺激方法测定三组家兔心室颤动阈值(VFT),离体测定心外膜、中层心肌和心内膜心肌细胞的单相动作电位复极90%时程(MAPD90)、跨室壁复极离散度(TDR)。结果:与正常对照组相比,扩张型心肌病组VFT明显降低(P<0.001),三层心肌细胞MAPD90均明显延长(P<0.001),中层心肌细胞较心外膜、心内膜下心肌细胞延长更为显著(P<0.05)。而卡维地洛组心外膜、心内膜MAPD90较扩张型心肌病组延长(P<0.05),但中层心肌MAPD90较扩张型心肌病组延长无明显差异(P>0.05)。与扩张型心肌病组相比,卡维地洛组TDR明显减小。结论:卡维地洛能降低扩张型心肌病的跨室壁复极不均一性,故能降低扩张型心肌病的心律失常发生率。

To observe the effect of carvedilol on transmural heterogeneity of ventricular repolarization in dilated cardiomyopathy(DCM), 24 rabbits were randomly divided into DCM, carvedilol and control groups. We used doxorubicin intravenously for 8 weeks to creat rabbit models of DCM, and in carvedilol group the rabbits carvedilol were orally given oral for 8 weeks. Then ventricular fibrillation threshold(VFT) was detected in vivo with nonprogrammed stimulation technique. And we evaluated monophasic action potential duration at 90% repolarization (MAPD_(90)) in epicardial, midmyocardial,and endocardial layers and transmural dispersion of repolarization (TDR) in vitro. Results: In comparison with control group, VFT in DCM group was apparently decreased, but the MAPD_(90) was prolonged in three myocardial layers and the prolongation of MAPD_(90) in midmyocardial layer was much more than that in epicardial and endocardial layers. MAPD_(90) of epicardial and endocardial cells in carvedilol groups was longer than that in DCM group (P<0.05), but there were no significant difference in MAPD_(90) of midmyocardial layer between DCM group and carvedilol group. So TDR of carvedilol group was significantly decreased in comparison with that of DCM group. Conclusion: Carvedilol has an effect on decreasing transmural heterogeneity of ventricular repolarization in rabbit with dilated cardiomyopathy, so it can reduce the incidence of arrhythmia of dilated cardiomyopathy.