Giant atrial septal aneurysm prolapsing into the right ventricle in an asymptomatic infant

A 10-month-old girl was referred to the pediatric cardiology clinic due to a cardiac murmur. On initial physical examination her second heart sound was somewhat more widely split with inspiration, and a grade 1-2/6 systolic ejection murmur was heard at the pulmonic region. The echocardiogram revealed a very large fenestrated atrial septal aneurysm with marked mobility, prolapsing from the tricuspid orifice into the right ventricle (Fig. 1 and Video 1). Color-image echocardiography demonstrated a patent foramen ovale and a multi-fenestrated atrial septum