Isolated Sub-Pulmonic Valve Endocarditis in a Patient With a History of Konno Procedure and Mechanical Aortic Valve.

Pulmonic and sub-pulmonic valve endocarditis are rarely encountered in clinical practice. We present the first case of isolated sub-pulmonic endocarditis. A 30-year-old man with a history of mechanical aortic valve presented to the emergency department with multiple complaints including nausea, vomiting, body aches, and fevers. The patient underwent surgical resection for sub-aortic stenosis followed by a modified Konno procedure later in life. A modified basal short-axis view on the trans-thoracic echocardiogram revealed a sub-pulmonic mobile structure highly suggestive of infective endocarditis. Blood cultures grew methicillin-sensitive  within 24 hours. Higher oxygen demand prompted chest imaging, chest CT showed the development of bilateral airspace consolidation, suggestive of pneumonia. After treatment with extended intravenous antibiotics, follow-up echocardiogram four months later showed no identifiable sub-pulmonic vegetation. This case describes a situation where clinicians may suspect infective endocarditis in a typical location such as a mechanical aortic valve. However, in patients who develop pneumonia, infective endocarditis of the right heart should be suspected. The pulmonic valve and sub-pulmonic ridge are often difficult to image given their anatomical location, a modified basal short-axis view on trans-thoracic echocardiogram can better image these structures.