B50-33 The EKG Told the Story: Early Conduction Changes Predicting Prosthetic Valve Infective Endocarditis Despite Negative Imaging

Abstract Introduction Infective endocarditis (IE) affects approximately 3-22 per 100,000 persons annually in the United States. Nearly one-third of cases are procedure-related, reflecting the growing use of prosthetic valves, implantable devices, and catheters. IE is a critical illness with an in-hospital mortality rate of 15-20%. We present an 82-year-old woman with a prosthetic valve who was treated for IE based on clinical suspicion, despite negative imaging, with further diagnostic imaging revealing a vegetation later in the clinical course. Case Presentation An 82-year-old female with a history of severe aortic stenosis status post transcatheter aortic valve replacement (TAVR) one year prior presented after a mechanical fall. She had a febrile episode and leukocytosis on admission. Initial workup was positive for methicillin-sensitive Staphylococcus aureus bacteremia and she was started antibiotics. Electrocardiogram (ECG) revealed sinus rhythm with new first-degree atrioventricular block (PR interval 301ms) and new left bundle branch block. Initial transthoracic echocardiogram (TTE) and transesophageal echocardiogram (TEE) showed a small patent foramen ovale (PFO), however no abscess or vegetations. Computed tomography (CT) head demonstrated embolic phenomena including a 4 mm focal hemorrhage and CT abdomen showed multiple splenic infarctions. Magnetic resonance imaging (MRI) brain confirmed an acute lacunar infarct and several acute parenchymal and subarachnoid hemorrhages. Tagged white blood cell single photon emission computed tomography (SPECT) showed no evidence of abnormal radiotracer uptake. Subsequent TEE showed a 2 cm mobile vegetation on prosthetic valve leaflets. Three weeks after the initial presentation, she underwent a successful TAVR explant and aortic valve repair. Discussion and Conclusion This case underscores the varying clinical presentation of IE, its propensity for multisystemic embolic events, and the critical importance of early diagnosis to optimize patient outcomes. Initial negative TEE can occur in 5-27% of cases. Interval TEE is recommended if clinical suspicion remains high. Conduction changes are more common in patients with prosthetic valves, with first degree heart block found in 11.5% of IE cases. ECG changes are associated with more severe disease and higher mortality rates. The risk of embolization in IE is 10-50%, with known risk factors including a Staph aureus infection, vegetation size greater than 10 mm, no improvement with targeted antibiotic therapy, and presence of a PFO. Physicians should maintain a high index of suspicion for IE in patients with prosthetic valves presenting with cardiac conduction changes and embolic phenomena, despite negative imaging. This abstract is funded by: None