Etiologies of atrioventricular block in young patients: A single-center study in China.

Background: Atrioventricular block (AVB) is common in the elderly and therefore considered to be a degenerative disease of the cardiac conduction system. However, there exist other etiologies contributing to AVB in young patients. This study aimed to determine the etiologies in patients aged before 60 years receiving their first pacemaker implantation for AVB in China.

Methods and results: Medical records and diagnostic tests of AVB patients were reviewed to identify the etiologies between 2010 and 2021 at Guangdong Provincial People's Hospital. Eight hundred and twenty-six patients (median age 47 years; 47.9% males) were included. The etiologies were identified in 336 (40.7%) cases, including complications to cardiac surgery (n = 190 [23.0%]), myocarditis (n = 57 [6.9%]), myocardial infarction (n = 25 [3.0%]), complications to catheter-based interventional procedures (n = 21 [2.5%]) and others (n = 43 [5.2%]). AVB caused by myocardial infarction was more common in men (5.8% vs. 0.5%, p < .001), while women received pacing treatment earlier (48 vs. 46 years, p = .019). Men were more likely to suffer from dilated cardiomyopathy (6.6% vs. 2.1%, p = .001) and atrial fibrillation/flutter (23.0% vs. 12.8%, p < .001). The number of first pacemaker implantation increased with age especially among patients with unclear etiologies.

Conclusion: The etiology of AVB was only determined in approximately 40% of patients receiving their first pacemaker implantation aged before 60 years. The predominance of AVB with unknown etiology and potential gender differences warrants further studies.