Left atrial appendage mimicking an intra-cardiac vegetation in preterm neonates

Infective endocarditis is emerging as a significant cause of morbidity in the neonatal intensive care with an incidence ranging from 0.07 to 4.3%. The rise in incidence may be explained by the increasing availability of echocardiography facilities in the neonatal unit. The diagnosis of infective endocarditis has major therapeutic implications as the neonate is treated with potentially toxic drugs and exposed to prolonged intravenous catheters. However, the consequences of a missed diagnosis of endocarditis in preterm neonates are unknown and may potentially lead to significant long-term cardiac complications. Onsite echocardiography in the neonatal unit by neonatologists may improve the speed of diagnosis in cases of endocarditis. However, lack of adequate training and experience in normal echocardiographic views may increase the false-positive rate. The posterior mitral valve leaflet is rarely affected due to the low velocity of blood passing through and because of the absence of prosthesis. We report 2 cases of the left atrial appendage rarely mimicking a posterior mitral valve leaflet vegetation, leading to an erroneous diagnosis of infective endocarditis. The features which distinguish the left atrial appendage from a posterior mitral valve leaflet vegetation are illustrated.