Aortic Root Abscess Causing Atrioventricular Block in a Patient With Infective Endocarditis: A Fatal Case.

Aortic root abscess is a rare but serious complication of infective endocarditis (IE), which can lead to conduction abnormalities such as atrioventricular (AV) block. We describe a case of a 48-year-old man with end-stage renal disease on hemodialysis who presented with weakness and recurrent falls, later found to have methicillin-sensitive Staphylococcus aureus bacteremia originating from a dialysis catheter. Despite appropriate antibiotic therapy and catheter removal, the patient developed a new first-degree AV block, which progressed to a high-grade block. Transesophageal echocardiography revealed a large vegetation at the base of the aortic valve with aneurysmal calcifications and suspected aortic root abscess, later confirmed on cardiac MRI. Due to significant comorbidities, he was not a surgical candidate and ultimately deteriorated into shock and died despite long-term antibiotic treatment. This case underscores the need for high clinical suspicion for intracardiac abscesses in patients with IE and new conduction disturbances, as early diagnosis and surgical intervention are critical to improving outcomes.