双嘧达莫对兔心肌缺血预处理心电生理效应的影响

Influences of Dipyridamole on Electrophysiological Effects of Ischemic Preconditioning in Rabbits′ Hearts

目的：观察双嘧达莫对兔心肌缺血预处理心电生理效应的影响。方法：采用新西兰兔建立心肌缺血再灌注模型，随机分为４组，其中１组为对照组，其余３组分别予以缺血预处理、双嘧达莫０２５ｍｇ／ｋｇ静脉注射和两者联合处理。应用心脏程序电刺激技术测定心室电生理参数及心室颤动阈值。结果：缺血预处理明显降低缺血再灌注损伤后心室有效不应期离散度、心室恢复时间离散度及双极心室电图ＱＴ间期离散度（分别为１５０ｍｓｖｓ２３６ｍｓ，Ｐ＜００１，１０６ｍｓｖｓ２２１ｍｓ，Ｐ＜００１，１３１ｍｓｖｓ２２９ｍｓ，Ｐ＜００１），提高心室颤动阈值（３０８ｍＡｖｓ２０６ｍＡ，Ｐ＜００１），减少室颤发生；联合应用双嘧达莫使有效不应期的离散度进一步下降（８８ｍｓｖｓ１５０ｍｓ，Ｐ＜００５），心室颤动阈值进一步提高（３６４ｍＡｖｓ３０８ｍＡ，Ｐ＜００５）。结论：缺血预处理增加心肌缺血再灌注损伤后心室电稳定性。

Objective: To study the influences of dipyridamole on electrophysiological effects of ischemic preconditioning in rabbits′ hearts. Methods: New Zealand rabbits were used to establish myocardial ishemia reperfusion models for this study. The models were divided into four groups. One group acted as control, while the other three groups received ischemic preconditioning, intravenous injection of 0 25 mg/kg dipyridamole in bolus and combination of these two treatments respectively. Programmed electric stimulation techniques were used to analyse the ventricular electrophysiological properties and to measure ventricular fibrillation thresholds. Results: Ischemic preconditioning significantly diminished the dispersion of ventricular effective refractory period (15 0 ms vs 23 6 ms), recovery time (10 6 ms vs 22 1 ms) and QT interval of bipolar electrogram (13 1 ms vs 22 9 ms), elevated the ventricular fibrillation threshold (30 8 mA vs 20 6 mA). When combined with dipyridamole pretreatment, the dispersion of ventricular effective refractory period was diminished (8 8 ms vs 15 0 ms) and the ventricular fibrillation threshold was elevated (36 4 mA vs 30 8 mA) further. Conclusion: Dipyridamole increased the effects of ischemic preconditioning on ventricular electric stability after ischemiareperfusion injury.