In this report, we presented two cases of infant patients who underwent transvenous endocardial implantation with SelectSecure™ 3830 pacing leads. Both patients were followed up for 5 years and 1.5 years, respectively, and their pacing parameters remained stable, indicating a successful treatment outcome with good efficacy and safety.
The 3830 lead is a lumenless active fixed lead with a thin diameter of 4.1 Fr, making it the thinnest pacing lead currently available. Despite its thinness, it exhibits high anti-extrusion properties, making it the preferred choice for transvenous pacing in children. Clinical research studies6–8 have highlighted the advantages of the 3830 lead in cardiac pacing, including its durability, ease of implantation, and low complication rates, making it particularly suitable for pediatric patients and those with congenital heart disease.
However, selecting the appropriate age and body shape for transvenous lead implantation in infants remains a challenge. Endocardial lead implantation offers advantages such as non-thoracotomy, reduced trauma, shorter hospital stays, lower pacing thresholds, and longer battery life. However, this is not suitable for cases with intracardiac shunts. The disadvantage is that the incidence of venous occlusion is high,9 and the physique is too small to be suitable. Generally, it is recommended for children weighing over 10 kg,10 and those with anatomical abnormalities preventing lead placement through veins should not be considered.
Compared to endocardial pacing, epicardial pacing is more invasive and has higher pacing thresholds, making it more susceptible to lead breakage and shorter battery life, and it can cause more coronary artery compression.11, 12 It is suitable for a small number of children with difficult endocardial access. In 2013, a retrospective analysis13 showed the results of a single centre over the past 26 years. A total number of 287 patients with congenital heart disease (CHD) with a median age of 5 (1–11 years) underwent cardiac pacing. Endocardial systems (Endo) were implanted in 117 patients, while epicardial systems (Epi) were implanted in 170 patients. The median follow-up period was 5 years (2–10 years). The pacing system failed in 29% of patients, which were 13% in Endo and 40% in Epi. Multivariate analysis showed a significantly higher risk of failure for Epi, a lower implant age, and a greater number of leads implanted. Endocardial systems of children with pacing showed significantly better results than Epi systems. Endocardial pacing also showed better long-term results than epicardial pacing. Another study 2 also suggested that the predictors of lead failure included young age at the time of implantation, CHD, and epicardial lead implantation. Epicardial lead is more likely to fail due to lead breakage or outlet block, while the transvenous endocardial lead mostly fails due to insulation layer fracture of lead displacement.
The second case presented in this report initially had epicardial pacing due to the child's low body weight. However, after 16 months, a significant increase in the pacing threshold of the epicardial lead was observed, resulting in impaired pacing function and subsequent episodes of syncope. This case highlights the importance of choosing endocardial lead pacing whenever possible and the need for close follow-up to detect lead failure and avoid potential accidents due to pacemaker failure.
Implantation of the 3830 lead requires the assistance of a delivery sheath (Medtronic™ C315, C304 sheath), which facilitates precise placement of the pacing lead in the cardiac cavity. The C315 sheath, particularly the S4/S5 delivery sheath, is commonly used in infant patients. The 3830 lead's thinness and anti-traction properties help reduce tricuspid regurgitation and subclavian vein compression syndrome.
To ensure successful and long-term pacing in infant patients, it is crucial to reduce lead failure and replacement rates while selecting appropriate pacing locations to minimize the impact on cardiac function. Although evidence suggests no significant difference in clinical results between right ventricular septum and apical pacing, right ventricular septal pacing offers advantages such as narrower QRS waves, better cardiac function maintenance,2, 14 and a lower incidence of perforation15, making it more suitable for clinical practice. The delivery of the 3830 lead through the preformed sheath improves operability, 6 making it easier to select the precise ventricular septal pacing location and achieve satisfactory pacing effects. Both infants in our cases had the endocardial pacing lead successfully placed in the middle portion of the right ventricular septum, resulting in relatively short QRS wave durations, though not reaching the ideal durations of physiological pacing. Further studies are required to explore the feasibility, safety, and risks of bundle of His system pacing in infants.
In conclusion, the implantation process of the 3830-lead pacemaker is manageable and effective. For infant patients under two years old with high atrioventricular block and bradycardia, transvenous endocardial implantation of the 3830 lead into the right ventricular septum for pacing is a safe and viable option. The 3830 lead can be successfully and safely utilized in pediatric patients as they grow and develop.