INTRODUCTION
Accessory mitral valve tissue (AMVT) is a rare cardiac anomaly in
developing endocardial cushions. Frequently,it is associated with either
simple or complex congenital heart disease, and rarely does it exist as
an isolated lesion. Most symptoms occur when patients have a left
ventricular outflow tract (LVOT) gradient of ≥50 mm Hg. Therefore, it is
rare to discover an asymptomatic patient without LVOT obstruction.
Accessory mitral valve tissue is usually diagnosed incidentally with
complaints of chest pain, palpitations, dyspnea, and syncope in
childhood.1-6 Surgical excision of isolated AMVT is
required when there is significant obstruction of the LVOT and is
associated with other cardiac abnormalities. Echocardiography provides
important information about the morphology and hemodynamic significance
of AMVT.6-8
Here, we present a patient with atrial septal defect (ASD) who was
incidentally found to have AMVT on echocardiogram. Interestingly, the
patient’s accessory mitral valve remained undetected for years until he
became symptomatic.