Subvalvular Aortic Membrane Masquerading as Valvular Aortic Stenosis

Discrete subvalvular aortic membrane is an unusual cause of left ventricular outflow tract obstruction. While commonly presenting during childhood, one quarter of the individuals are asymptomatic in childhood but remain vulnerable to progressive outflow tract obstruction as well as bacterial endocarditis in adulthood. Unfortunately, because the condition is so uncommon in adults, the diagnosis of subvalvular membrane is often missed or delayed. We recently had the opportunity to care for an adult patient who finally had subvalvular membrane identified as the cause of a left ventricular outflow obstruction, only after a protracted series of diagnostic investigations. Pitfalls in the noninvasive and invasive diagnosis of this condition are reviewed.