[Analysis of the safety and efficacy of endocardial permanent pacemaker implantation in infants]

Objective: Evaluate the safety and efficacy of permanent endocardial pacemaker implantation in infants. Methods: This study was designed as a retrospective cohort study. Infants with complete atrioventricular block who underwent endocardial permanent pacemaker implantation at Fujian Children's Hospital from 2021 to 2023 were selected. Clinical, electrocardiographic, echocardiographic, pacemaker parameters data and implantation-related adverse events were collected and analyzed during follow-up. Results: Eight infants were enrolled, with a surgical age of 5.8 (3.0, 7.0) months and a body weight of 5.6 (5.2, 7.0) kg. Three (3/8) were male. Etiologies included congenital complete atrioventricular block (n=5) and acquired complete atrioventricular block (n=3). The preoperative QTc interval was (469±38) ms, with a left ventricular end diastolic diameter Z score of 1.83±1.58, and a left ventricular ejection fraction of (62.1±15.7)%. Intraoperative pacemaker parameters were as follows: threshold 0.5-1.3 V/0.4 ms, sensing amplitude 2.0-21.2 mV, and impedance 500-700 Ω. Over a follow-up of 16.0 (6.0, 21.8) months, significant improvements were observed at the 3-month postoperative assessment: QTc interval shortened to (427±29) ms, left ventricular end diastolic diameter Z score decreased to 0.20±1.00, and left ventricular ejection fraction increased to (64.9±4.1)%. At 6 months postoperatively, the threshold was 0.4-1.0 V/0.4 ms, sensing amplitude 4.9-10.1 mV, and impedance 521-1 462 Ω. Notably, patients with preoperative cardiac dysfunction (n=1), significant left ventricular dilation (n=5), or prolonged QTc with ventricular arrhythmias (n=5) showed essentially normal recovery. One patient developed moderate-to-severe tricuspid regurgitation one week after surgery, which was successfully reduced to mild-to-moderate following a secondary procedure for lead repositioning two weeks later. All eight patients demonstrated good pocket healing, with no instances of ipsilateral upper limb swelling or formation of superficial collateral vessels during the follow-up period. No implant-related adverse events occurred. Conclusion: Permanent endocardial pacemaker implantation in infants demonstrates acceptable safety and efficacy profiles. This treatment can be attempted with strict control of surgical indications and meticulous operation.