Fig. 1.

Echocardiographic findings. Representative four-chamber views. (A) Transthoracic echocardiography demonstrating the unguarded mitral valve orifice (white arrow), thinned left ventricle walls, and a large primum atrial septal defect. (B) Diastolic frame demonstrating color-flow Doppler through the mitral valve and tricuspid valve. (C) and (D) Systolic frame reveals free regurgitation of the unguarded mitral orifice and severe regurgitation of the tricuspid valve. lRA, left-sided morphologic right atrium; rRA, right-sided morphologic right atrium; RV, right ventricle; LV, left ventricle.