Author: Kaitlin M. Flannery, MD, MPH - Stanford University
A 16-year-old, 70 kg patient with a history of orthotopic heart transplantation for dilated cardiomyopathy presents with acute rejection secondary to medication noncompliance. During hospitalization, the patient is noted to have intermittent high-grade second-degree atrioventricular block (AV block), particularly during sleep. Permanent pacemaker implantation is recommended, and the decision is made to place a transcatheter leadless pacemaker (TLP). Which of the following is the MOST likely reason a TLP was chosen for this patient?
EXPLANATION
Transcatheter leadless pacemakers (TLP) are designed to eliminate components of traditional epicardial and transvenous pacemaker systems that are responsible for many common complications, namely leads and the subcutaneous device pocket. Complications associated with conventional permanent pacemakers include lead fractures, venous obstruction, tricuspid valve injury, pocket infection, and Twiddler syndrome.1
TLPs are approximately the size of a large multivitamin and are implanted directly into the right ventricular interventricular septum via femoral or internal jugular venous access. These devices have been available in Europe since 2013 and in North America since 2016, with over 150,000 adult patients having undergone implantation.1 Since then, a TLP designed for device retrieval as well as the dual-chamber device which achieves atrioventricular synchrony through wireless communication between two devices implanted in the right atrium and right ventricle have been developed.1
Most available data on TLP comes from adults, as no randomized controlled trials have been conducted in pediatric patients. The Pediatric & Congenital Electrophysiology Society established a TLP registry and published retrospective data on 63 patients ≤ 21 years of age who underwent Micra TLP implantation between May 2016 to May 2021. Successful implantation occurred in 62 patients. The single unsuccessful case involved a patient with Emory-Dreifuss muscular dystrophy, in whom high pacing thresholds precluded implantation. The cohort had a mean age of 15 ± 4.1 years and a mean weight of 55 ±19 kg. Eight patients were ≤ 8 years old and weighed ≤ 30 kg; the youngest patient was 4 years old and weighed 16.7 kg. Congenital heart disease was present in 32% of patients. Femoral venous access was used in 87% of cases, while internal jugular access was more common in patients ≤ 8 years old. All procedures were performed under general anesthesia, with transesophageal echocardiographic guidance used in 22% of cases. Procedural duration ranged from 20-294 minutes (mean 98 minutes). Indications for pacemaker implantation included atrioventricular conduction disease (63%) and sinus node dysfunction (33%). No patients were pacemaker-dependent.1 Early complications occurred in 11% of patients, which included one failed implantation (described above), one pericardial effusion requiring pericardiocentesis, as well as three access-site bleeding events, one hematoma, and one arrhythmia during device placement.1
Indications for considering TLP in pediatric patients:
1. Inadequate vascular access for a transvenous system due to concerns for chronic venous occlusion
2. Preservation of vascular patency for future transvenous pacing systems or hemodialysis
3. Recurrent transvenous or epicardial lead failure
4. History of device pocket infection
5. High surgical risk associated with redo sternotomy or thoracotomy for epicardial pacemaker
Limitations of TLP use in pediatrics:
1. Large delivery system (27 French)
2. Technical challenges related to smaller right ventricular size
3. Uncertainty regarding long-term device retrieval2
4. Risk of right ventricular crowding and obstruction if multiple devices are retained
5. Limited ability to support the higher heart rates often required in pediatric patients
Anesthesia providers must remain aware of evolving pacemaker technologies and their perioperative implications. Physical examination will not reveal a device in traditional chest or abdominal pocket locations. Chest radiography can confirm device position (see image below). Magnets do not affect the function of TLPs. In pacemaker-dependent patients undergoing procedures requiring electrocautery, the device must be reprogrammed to an asynchronous pacing mode.3
In this scenario, the patient is at an increased risk of infection from immunosuppression, making TLP insertion an important additional consideration. Leadless cardiac resynchronization therapy is not currently available, and the delivery system remains relatively large.4
REFERENCES
1. Shah MJ, Borquez AA, Cortez D, et al. Transcatheter Leadless Pacing in Children: A PACES Collaborative Study in the Real-World Setting. Circ Arrhythm Electrophysiol. 2023;16(4):e011447. doi:10.1161/CIRCEP.122.011447
2. Curnis A, Cerini M, Mariggiò D, et al. First-in-human retrieval of chronically implanted Micra transcatheter pacing system. Pacing Clin Electrophysiol. 2019;42(7):1063-1065. doi:10.1111/pace.13622
3. Karuppiah S, Prielipp R, Banik RK. Anesthetic consideration for patients with micra leadless pacemaker. Ann Card Anaesth. 2020;23(4):493-495. doi:10.4103/aca.ACA_191_19
4. Joza J, Philippon F, Chew DS, et al. Current Challenges in Cardiac Device Management: Guidance for Practicing Clinicians: A Canadian Journal of Cardiology White Paper. Can J Cardiol. 2026;42(1):101-135. doi:10.1016/j.cjca.2025.05.020