Objective:To analyze the factors associated with atrial fibrillation(AF)in patients with apical hypertrophic cardiomyopathy(ApHCM).Methods:One hundred and twenty-five patients with apical hypertrophic cardiomyopathy were consecutively enrolled from Beijing Anzhen Hospital affiliated with Capital Medical University from April 2011 to April 2019,of whom 49 cases were diagnosed with atrial fibrillation(observation group)and 76 without atrial fibrillation(control group),with a mean age of 65.5 years in the atrial fibrillation group and a proportion of 59.2%males,and a mean age of 59.5 years in the control group,with a proportion of 84.2%males.Age,gender,co-morbidities,treatment,and echocardiographic findings were collected,and univariate and multivariate Logistic regression analyses were used to assess the association with atrial fibrillation in patients with ApHCM.Results:Compared with the control group,the patients in the AF group was older,had a higher New York cardiac function class Ⅲ,a lower proportion of percutaneous coronary intervention,a higher proportion of radiofrequency ablations,and a longer hospital stay(P<0.05).There were no significant differences in cardiac ultrasound parameters between the two groups(P>0.05).Multifactorial Logistic stepwise regression analysis showed that female(OR=3.170,95% CI:1.124-8.942,P=0.029),left atrial anteroposterior diameters(OR=1.287,95% CI:1.149-1.440,P=0.000)were the independent risk factors for the occurrence of atrial fibrillation in this population,and the thickness of the left ventricular posterior wall was negatively correlated with atrial fibrillation(OR=0.690,95% CI:0.484-0.984,P=0.041).Conclusions:Atrial fibrillation is one of the key factors affecting ApHCM and has a high prevalence,while female and left atrial anterior and posterior wall diameter are independent risk factors for the occurrence of AF,so it is particularly important to target and individualize treatment according to the population.