Long-term follow-up in pacemaker recipients after orthotopic transplantation

Background:
The incidence of pacemaker implantation following orthotopic heart transplantation (OHT) ranges from 2% to 24%. While most patients maintain sinus rhythm post-transplantation, pacemaker implantation may become necessary due to sick sinus syndrome or atrioventricular conduction disturbances. These procedures can be technically challenging, particularly in patients who have undergone biatrial anastomosis techniques. Furthermore, long-term data on pacemaker system stability and lead performance in heart transplant recipients remain limited.
The objective of this study was to assess the incidence, feasibility, and long-term outcomes of pacemaker implantation in heart transplant recipients, with the aim of evaluating the safety of the procedure in this patient population.

Methods:
A prospective analysis was conducted using data from the institutional registry, encompassing all patients who underwent OHT between 2009 and 2022. Baseline characteristics, procedural details, and follow-up outcomes were analyzed. Data are presented as mean ± standard deviation or median with interquartile range (IQR), as appropriate. The composite study endpoint included implantation-related complications, pacemaker system dysfunction, and device-related infections.

Results:
From 2009 to 2022, a total of 1.080 orthotopic heart transplants were performed at our center (914 with biatrial and 166 with bicaval techniques). Of these, 117 patients (10.8%) required pacemaker implantation, indicated for sick sinus syndrome in 75 patients (64.1%) and for high-grade atrioventricular block in 38 patients (32.5%). A dual-chamber system was used in 116 cases, and one patient received a leadless pacemaker. The median time from transplantation to pacemaker implantation was 48 days [IQR: 30–216], with 31 patients (26.5%) receiving a device within 30 days post-transplant.
Left- and right-sided pacemaker implantation approaches were employed in 48 patients (41.0%) and 68 patients (58.1%), respectively. The mean procedure duration was 75.1 ± 25.1 minutes, with a mean fluoroscopy time of 276.4 ± 470.9 seconds. Periprocedural complications occurred in 5 cases (4.3%) with pocket hematomas not requiring surgical correction.

The mean follow-up duration was 2.082±1.426 days, with 96 patients (82.1%) alive at the end of the observation period. Electrical parameters were within normal limits at the time of implantation and remained stable throughout the follow-up period (Table 1). The composite study endpoint occurred in 13 patients (11.1%) after a median of 17 days [IQR: not specified], comprising 9 right atrial lead revisions due to dysfunction, 2 right ventricular lead revisions, and 2 cases of device-related infection.

Conclusion:
This single-center study demonstrates that pacemaker implantation in orthotopic heart transplant recipients is both safe and feasible. Lead performance remained stable over long-term follow-up, and the incidence of pacemaker-related complications was low, predominantly involving dysfunction of the right atrial lead.

Table 1 Electrical parameters