Introduction
Atrial septal defects (ASD) with more than 1.5:1 left to right shunts
warrant closure by intervention or surgery. Interventional closure of
ASDs is the preferred treatment modality if the rims of ASD are amenable
to device closure. Deficiency of rims (< 5mm) is considered a
contraindication for device closure of ASDs(1). The inferior vena cava
rim and the atrioventricular valve rim are the most important borders to
be assessed when considering a patient for device closure. ASD device
closure has been attempted in patients with a borderline mitral rim if
the other rims are adequate. Instability of the device and development
of conduction disturbances and heart block have been attributed to
attempted device closure in deficient atrioventricular valve rims
because of the close proximity to the AV node. Eustachian valve
frequently interferes with the proper deployment of device. Here, we
describe a patient with borderline mitral rim where ASD device closure
was successful because of the added stability provided by a prominent
Eustachian valve.