摘要BACKGROUND His bundle pacing (HBP) and left bundle branch pacing (LBBP) both provide physiologic pacing which main-tain left ventricular synchrony. They both improve heart failure (HF) symptoms in atrial fibrillation (AF) patients. We aimed to assess the intra-patient comparison of ventricular function and remodeling as well as leads parameters corresponding to two pa-cing modalities in AF patients referred for pacing in intermediate term. METHODS Uncontrolled tachycardia AF patients with both leads implantation successfully were randomized to either modal-ity. Echocardiographic measurements, New York Heart Association (NYHA) classification, quality-of-life assessments and leads parameters were obtained at baseline and at each 6-month follow up. Left ventricular function including the left ventricular endo-systolic volume (LVESV), left ventricular ejection fraction (LVEF) and right ventricular (RV) function quantified by tricuspid an-nular plane systolic excursion (TAPSE) were all assessed. RESULTS Consecutively twenty-eight patients implanted with both HBP and LBBP leads successfully were enrolled (69.1 ± 8.1 years, 53.6％ male, LVEF 59.2％ ± 13.7％). The LVESV was improved by both pacing modalities in all patients (n = 23) and the LVEF was improved in patients with baseline LVEF at less than 50％ (n = 6). The TAPSE was improved by HBP but not LBBP (n =23). CONCLUSION In this crossover comparison between HBP and LBBP, LBBP was found to have an equivalent effect on LV function and remodeling but better and more stable parameters in AF patients with uncontrolled ventricular rates referred for at-rioventricular node (AVN) ablation. HBP could be preferred in patients with reduced TAPSE at baseline rather than LBBP.