In Doubt Take It Out? Diagnostic and Therapeutic Management of Leadless Pacemaker Endocarditis in a Pacemaker-Dependent Patient

Background:

Leadless pacemakers (LLPs) offer a safe alternative to conventional pacemaker systems, and the indications and methods for their explantation are well-documented. However, there is limited data on the management of leadless pacemaker endocarditis in pacemaker-dependent patients. This case report describes the catheter-based extraction of a leadless pacemaker system, the unusual presentation of device-associated endocarditis (sCDE) and the subsequent management of the patient.

Case summary:
A 73-year-old dialysis-dependent patient with multiple comorbidities was referred for explantation of a MICRA leadless pacemaker due to suspected CDE. The patient had experienced recurrent fever and elevated inflammatory markers for four months. The pacemaker was implanted in February 2023 for symptomatic bradycardic atrial fibrillation. Initial infection screening, including blood cultures and transesophageal echocardiography, did not detect pathogens or vegetations. A PET-CT scan showed significant tracer uptake in the MICRA area,prompting the initiation of empirical antibiotic therapy. Pacemaker function was normal, with no dependency observed. Given the MICRA’s persistence as the only possible infection focus, the decision was made to proceed with explantation.The procedure was performed under general anesthesia with cardiac surgical standby. A femoral 23F sheath was placed, followed by a short 12F sheath to reduce retrograde blood flow. A steerable sheath (8.5F, Agilis) and a snare loop catheter were introduced and the MICRA was ensnared and carefully retrieved. The pacemaker was successfully removed through the 23F sheath without complications. Postoperative blood cultures and microbiological examination of the MICRA revealed no pathogens.Despite this,anti-infective therapy was extended to fourteen days. During the course, the patient developed sick sinus syndrome with intermittent pauses of up to 14 seconds. Given the patient’s fever resolution and normal inflammatory markers, a VVI pacemaker (VVI-PM) was implanted. The patient completed the antibiotic regimen without issues and was discharged in stable condition. Follow-up visits showed no symptoms of infection, and the patient remained asymptomatic.

Discussion:
This report describes a rare case of MICRA-associated endocarditis occurring 13 months after implantation. The initial diagnosis of endocarditis was supported by clinical presentation and positive PET-CT tracer uptake. According to the modified DUKE criteria (2023),this case is classified as “possible endocarditis” (1 major, 1 minor criterion). The source of the infection remains unclear, but potential causes include transient bacteremia from recurrent pulmonary infections, a recent hip replacement, or frequent dialysis treatments. The underlying cause could not be definitively identified on clinical or PET-CT evaluation. Despite no indication of sick sinus syndrome during pacemaker checks, the patient developed this syndrome post-explantation, which led to the decision to implant a VVI pacemaker instead of re-implanting the MICRA. Alternative management strategies, including conservative treatment with antimicrobial therapy or re-implantation of an LLP,could also be considered in similar cases.

Conclusion:
This case report highlights the unusual clinical presentation of a Leadless Pacemaker-associated endocarditis and the individualized therapeutic decision-making involved in treating a pacemaker-dependent patient.