Abstract: Objective To explore the clinical characteristics and prognosis of fetuses with complete atrioventricular conduction block (CAVB). Methods The clinical characteristics, treatment and outcome of 13 fetal CAVB patients diagnosed by the 900TH Hospital of Joint Logistics Support Force from January 2012 to August 2022 were retrospectively analyzed. Results A total of 13 CAVB fetuses were included, of whom 7 were terminated and 6 survived. Among the 7 terminated fetuses, 6 were complicated with decreased cardiac function, 5 had cardiac structural abnormalities, and mothers of 4 fetuses were positive for ANA and SSA antibodies. Among the 6 surviving fetuses, 1 case was complicated with decreased cardiac function, 2 cases had cardiac structural abnormalities, and mothers of 5 cases were positive for ANA and SSA antibodies. One child had a resting ventricular rate of 42-45 beats/min after birth. He was implanted with a permanent pacemaker because of sudden syncope at the age of 5 years. One patient had atrial septal defect with ventricular rate <70 beats /min. He underwent atrial septal defect repair without pacemaker implantation at the age of 2 years. The remaining 4 patients had ventricular rate >52 beats /min without pacemaker implantation.Conclusion If the CAVB fetus with normal cardiac function and normal cardiac structure has no obvious symptoms after birth, most of them have a good prognosis and permanent pacemaker implantation can be deferred.

Key words: fetus, complete atrioventricular conduction block, permanent pacemaker