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OBJECTIVE:To study the effect and mechanism of cilostazol in experimental anti-bradyarrhythmia.MET-HODS:Bradyarrhythmia model of mice was induced using verapamil hydrochloride and nicotine,respectively.The electrocardiograms at different time and the heart rates of the model mice after intragastric administration of different dosages of cilostazol were recorded.The in vivo His' bundle electrogram(HBE)recordings in rabbits were obtained after intragastric administration of different dosage of cilostazol for detection of A-H interval and H-V interval,which were compared with control group(normal saline group).RESULTS:Verapamil hydrochloride and nicotine markedly slowed down the heart rates of mice,but cilostazol significantly sped up the heart rates in mice(P
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Objective To study the effects of heart ischemia reperfusion on conductive function of atrioventricular node (AVN) in rabbits. Methods Animal models of ischemia reperfusion of AVN were established by ligating and reopening the right coronary artery of rabbits. A total of 60 adult rabbits were divided into control groups ( n =10), right coronary artery occlusion group ( n =10), and ischemia reperfusion groups with ligation of the right artery occlusion for 10, 30, 60 and 120 min respectively ( n =10 for every subgroup). The hemodynamics, His bundle electrography and epicardial electography were carried out and recorded. Results After occlusion of right coronary artery, 94.8% animals in experimental groups were found to have prolonged atrial His interval (AH) ( P
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Objective To study the effect of moxonidine (Mox) on the His bundle electrogram (HBE) of normal rabbits. Methods A total of 24 healthy rabbits were randomly divided into four groups: control group, small dose of Mox (0.1 mg?kg -1), medium dose of Mox (0.3 mg?kg -1) and large dose of Mox (0.9 mg?kg -1). The electrode catheter was inserted from the right carotid artery to record the HBE. The HBE and the synchronism surface ECG were recorded before and after intravenous injection. Results In normal rabbits, the R-R interphase, P-R interphase of the ECG and the H-V interphase of the HBE were prolonged in a dose-dependent manner after intravenous injection of Mox. Mox exerted no significant influence on the A-H interphase. Conclusion ① Mox decreases the heart rate of rabbits in a dose-dependent manner in vivo. ② Mox dose-dependently prolongs the P-R interphase of the surface ECG and the H-V interphase of HBE. This indicates that Mox mainly acts on the intraventricular conducting system.