房颤是临床常见的心律失常之一，而增龄是房颤发生的独立危险因素。研究指出，肺静脉和心房的起搏电流(If)和HCN通道对增龄性房颤的发生和维持起着重要作用。目前导管射频消融术是治疗房颤的首选方式，但也受年龄限制，而临床上并没有预防或降低房颤发生的药物。伊伐布雷定是一种离子通道抑制剂，可降低HCN通道的表达，减缓If的跨膜速度，是一种新型抗心律失常药物。研究指出，伊伐布雷定能够可作用于肺静脉和心房内的If，但是否可以降低增龄性房颤的发生，目前并未存在相关报道。本研究拟建立增龄性房颤犬模型，添加伊伐布雷定药物干预。通过观察伊伐布雷定对增龄性房颤犬电生理特性的影响，心房内If的分布、密度和稳态激活情况，观察心房和肺静脉If和HCN通道及相关指标的表达水平，心房结构重构和电重构变化，以期探讨伊伐布雷定对增龄性房颤的应用价值，为伊伐布雷定对增龄性房颤的治疗提供理论基础。

Atrial fibrillation is one of the common clinical arrhythmia, aging is an independent risk factor for atrial fibrillation. The funny current (If) and HCN channels from atrial and pulmonary vein plays an important role in age-related atrial fibrillation. Catheter ablation is the first choice for the treatment of atrial fibrillation, but it is also affected by age, and there is no clinical drug treatment to prevent or reduce the occurrence of atrial fibrillation. Ivabradine is one of ion channel inhibitor, can reduce HCN channels of expression and slow down transmembrane velocity of If , is a new antiarrhythmic drug. Research indicates that ivabradine can influence If transmembrane velocity in pulmonary vein and atrium, but whether it can reduce the incidence of age-related atrial fibrillation, there is no relevant reports. We sought to establish a dog model of age-related atrial fibrillation, adding ivabradine drug intervention. To investigate the effects of ivabradine to electrophysiological properties of aging atrial fibrillation, the distribution,density and the steady-state activation of If. To investigate the expression levels of If , HCN channles and other related index from atrium and pulmonary veins, the changes of atrial structural and electrical remodeling. To investigate ivabradine on aging atrial fibrillation value, provides age-treatment of atrial fibrillation.