Abstract: To investigate the effects of Captopril on left ventricular connexin remodeling during tachycardiainduced cardiomyopathy in canines. Methods Twenty-four dogs were randomly divided into 3 groups. In the pacing group, each dog was implanted with a permanent pacemaker (pacing at 350-450 bpm), the pacing electrode was implanted in the right atrial appendage through the external jugular vein. In the pacing and drug group, each dog was given Captopril 50mg twice a day three days before the pacemaker was implanted and through out the study. The pacing procedure was the same as in the pacing group. In the control group, no pacemakers or drugs were given. Before pacing and 1,4,8 weeks after pacing, the echocardiography and ECG were measured, and also the heart function was measured. After 8 weeks′ pacing, catheterization was used to assess the systolic and diastolic functions and the content of Cx43 was determined by confocal immunofluoroscopy. ResultsThe content of Cx43 was significantly different between the pacing group and the control group（P＜0.001）and between the pacing group and the pacing and drug group（P＜0.05）. Conclusions Captopril may prevent the decrease of the content of Cx43， and prevents gap junction remodeling in dogs with long-term rapid atrial pacing．

Key words: Tachycardia-induced cardiomyopathy, Captopril, Connexin