Background Atrial fibrillation (AF) is one of the common arrhythmia in clinical cardiac diseases, of which the morbidity is closely related with the age of the patients.AF may attack anyone, but it has a high morbidity in the aging and an extremely low morbidity in the children.The morbidity rate of AF is above 0.4％ among common people, the morbidity rate rises significantly with the increasing of the age, which reaches 6％ for those who are above 65, 10％ for those who are above 75 and even near 20％ for those who are above 85.The continuous existence of AF will cause serious complications easily such as heart failure, intraatrial thrombus and cerebral embolism, etc, which have a high disability rate and mortality rate.Currently, there are many therapeutic methods in treating AF, including drug therapy,electrical conversion, surgical maze operation treatment, radiofrequency catheter ablation and pacemaker implantation,etc, however, none of them is completely satisfactory, which calls for the study on the mechanism of AFs occurrence and maintenance.The function of neural regeneration in AF myoelectricity remodeling is gaining increasing attention in recent years.Tyrosine hydroxylase (TH) and growth associated protein 43 (GAP43) are important nerve growth factors,previous studies hold that the former is a sign factor of sympathetic nerve and the latter is a sign factor of parasympathetic nerve, TH and GAP43 may play a vital role in the process of AF formation, maintenance and recovery.This study intends to explain the role of the changes of gene and protein expression of TH and GAP43 in aging AF through detecting the changes of them in atrial tissues of AF patients of Xinjiang Uygur and Han nationality in different ages, in order to provide new theoretical basis for a better clinical AF therapeutics strategy.