(178) In Between Leads: Endocarditis Presenting With an Atrial Thrombus After Pacemaker Placement

Introduction: Infectious endocarditis (IE) is a potentially fatal condition which becomes a clinical challenge when the causing pathogen is difficult to diagnose. Blood cultures remain the standard diagnosing tool for guiding and optimizing antibiotic treatment, yet up to 20% of cases can present with negative blood cultures. The following case report presents a blood culture negative endocarditis developing bilateral lower extremity ischemia and a right atrial thrombus encircling a pacemaker lead.

Description: A 78 year old male with past medical history of hypertension presented to the emergency for dizziness for the last two weeks. His heart rate in the 30s, was diagnosed with a complete heart block and scheduled for a pacemaker placement. Before the procedure, he had a fever and persistent leukocytosis. A temporary transvenous pacemaker was placed and he was started on empiric antibiotic treatment for a week. Blood cultures were negative. Fever resolved and a permanent pacemaker was placed. His agitation, increased confusion, hypotension, marked leukocytosis, prompted admission to the ICU for concern of shock. Repeat blood cultures remained negative. Lumbar puncture was also done with negative results. Later, purplish discoloration of bilateral lower extremities with absent tibial pulses were present. Fibrinogen was noted to be low with elevation of coagulation factors, concerning for disseminated intravascular coagulation. Imaging studies showed deep venous thrombosis in tibial and popliteal veins bilaterally leading to critical limb ischemia. Transesophageal echocardiogram confirmed endocarditis with vegetation on aortic valve leaflet. It was also noted to have massive thrombus encircling right atrium pacemaker lead. Due to high risk interventions needed and worsening multisystem organ failure, patient and family decided hospice care.

Discussion: Diagnosing and treating IE remains challenging as it is associated with diverse presentations and variable clinical course. A low threshold should be maintained for considering the diagnosis of IE. This case is an opportunity to explore the wide range of presentations that IE may have. Cardiac embolization, while rare, can be a complication, which urges clinicians to have in mind the critical significance of timely recognition in cases of IE.