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Aims: The pacemaker current (abbreviated as If) is the major current in the action potential phase 4 auto-depolarization process,It played a key role in the formation and maintenance of heart rhythm.Atrial fibrillation is the most common arrhythmia in clinic, and the pathogenesis of atrial fibrillation was complex.We conducted a review to understand the relationship between the pacemaker current and atrial fibrillation.Methods:A systematic search of electronic databases (PubMed, EMBASE, Google Scholar) for studies published from 1970 to March 2012 was perforned.Clinic, animal studies that related to the pacemaker current on the mechanism of the atrial fibrillation were included.Results: The pacemaker current was coded by the hyperpolarization-activatid cyclic mucleotide cation gated channels (HCN) gene family.So far, it was known four members in HCN family: HCN1-4, and HCN1,2,4 were the major types expressed in the mammalian heart.The clinic researches have shown that the messenger ribonucleic acid (mRNA) of HCNs in the atrial tissue of atrial fibrillation patients was increased, indicated that the overexpress of HCN gene may regulate the generation of atrial fibrillation.The animal model of paroxysmal atrial fibrillation experiments also suggest that the pacemaker current may lead to the increase of the pulmonary vein (PV) sleeves ectopic self-regulation, and involve in the start mechanism of atrial fibrillation.Some studies demonstrated that ivabradine (an If blocker)decreased the spontaneous activity in PVcardiomyocytes through an inhibition of the If, which may imply the potential use for treating atrial fibrillation.Conclusions: The pacemakter current may involve in the genesis and maintain of atrial fibrillation.However, the exact mechanism of the occurrence and development of the pacemaker current in atrial fibrillation is still need for further researches to confirm.