Ping Lu, Xingchun Mo, Xiaojing Yang, Yaoyao Lin

Department of Cardiology, Linping Campus, Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China

Correspondence: Ping Lu, Department of Cardiology, Linping Campus, Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang Chinese Medical University, No. 369 Yingbin Road, Linping District, Hangzhou, 311100, Zhejiang, People’s Republic of China, Email lupingdr@21cn.com

Objective: Exploring the independent risk factors of second-degree atrioventricular block (II AVB) in patients with atrial fibrillation (AF), and to evaluate the clinical value of 24-hour dynamic electrocardiogram (DCG) in its diagnosis.
Methods: A prospective cohort study was conducted on 947 patients with AF diagnosed and treated in our hospital from January 1, 2021 to December 31, 2021. These patients were divided into combined group (98 cases) and uncombined group (849 cases) according to whether they were accompanied by. The clinicopathological data of the patients were collected, and Multivariate logistic regression analysis was used to analyze the independent risk factors. Patients in combined group were further evenly divided into the study group (underwent 24-hour DCG) and the control group (underwent routine ECG) based on the detection methods. The diagnostic value was valued and the positive detection rate was calculated by ROC curve.
Results: The smoking history, left atrial internal diameter (LAD), R-R interval and ventricular rate of patients in two groups had significant differences (P< 0.001). Smoking history (HR=1.531, 95% CI 1.150– 2.038, P< 0.001), LAD> 35.88 mm (HR=1.941, 95% CI 1.301– 2.895, P< 0.001), R-R interval> 2.50 s (HR=2.282, 95% CI 1.231– 4.229, P=0.014) were independent risk factors for AF combined with II AVB, while ventricular rate≤ 70 beats/min (HR=0.506, 95% CI 0.293– 0.873, P=0.014) were independent protective factors for AF combined with II AVB. The mean ventricular rate (70.03± 5.40 beats/min vs 83.11± 8.05 beats/min, P< 0.001) and R-R interval (2.82± 0.26s vs 2.37± 0.14s, P< 0.001) in the study group were longer than the control group. The diagnostic positive rate of DCG (97.96% vs 85.71%, χ²=4.900, P=0.027) was higher than that of conventional ECG.
Conclusion: Smoking history, LAD, R-R interval and ventricular rate were influential factors for AF combined with II AVB. 24-h DCG had potential diagnostic value in the occurrence of AF combined with II AVB.

Keywords: atrial fibrillation, second-degree atrioventricular block, influencing factors, dynamic electrocardiography, diagnostic value