Abstract： Background Radiofrequency catheter ablation (RFCA) necessarily produces an area of myocardial necrosis.However,the difference of the extent of myocardial injury between circumferential pulmonary vein isolation (CPVI) and complex fractionated atrial electrograms (CFAE) ablation in patients with atrial fibrillation (AF) has not been investigated before.Methods Twenty-nine consecutive male patients (n=29) with either paroxysmal or persistent AF were selected for CPVI or CFAE ablation.The CPVI or CFAE ablation was performed with a three-dimensional electroanatomical mapping system (CARTO).Serum cardiac biomarkers,for example,cardiac troponin T (cTnT),aspartate transaminase (AST),lactate dehydrogenase (LDH),creatine kinase (CK),and creatine kinase myocardial bound (CKMB) were determined by the Elecsys STATE immunoassay.Cardiac structure and function were measured with echocardiography.Results Echocardiography showed that there was no significant difference of atrioventricular structure or function parameters between the CPVI group and the CFAE ablation group.Serum cTnT showed a significant increase in the CFAE ablation group over the CPVI group at 12 and 24 hours after the procedure (P＜0.05,respectively),and then it was reduced to a normal level after 48 hours.Serum AST showed a significant increase in the CFAE ablation group over the CPVI group at post-procedure,4 and 12 hours after the procedure (P ＜0.05,respectively),and then it reached to a normal level after 24 hours.There was no significant difference in LDH,CK,or CKMB levels between the CFAE ablation group and the CPVI group at any time point (P＞0.05).Conclusions cTnT and AST other than LDH,total CK or CKMB activity significantly increased more in the CFAE ablation group than the CPVI group.However,the difference of the serum levels of cTnT,AST between two groups was temporary.