Quadricuspid Aortic Valve: A Rare Case of Endocarditis Suspicion and Management.

Quadricuspid aortic valve (QAV), a rare congenital cardiac anomaly, often presents with aortic regurgitation and can lead to significant cardiovascular complications. This case report describes a 55-year-old male with a history of subarachnoid hemorrhage who was incidentally found to have QAV with possible endocarditis. Transesophageal echocardiography revealed thickened leaflet tips on all four cusps and a mass on one leaflet, raising suspicion of endocarditis despite the absence of vegetation. The patient was treated with intravenous antibiotics for Gram-positive bacteremia, and follow-up imaging confirmed the QAV anomaly with moderate aortic regurgitation. This case highlights the challenges in diagnosing QAV, particularly in asymptomatic individuals, and underscores the need for comprehensive investigation, especially in those with a history of vascular events. It also emphasizes the importance of further research to clarify the long-term risks and optimal management strategies for individuals with QAV, including the potential for infective endocarditis.