A 1 month old infant has failure to thrive. On examination a heart murmur is auscultated over the chest. No cyanosis is noted.
Question
Echocardiography shows a left to right shunt just above the muscular interventricular septum. An abnormality of which of the following structures most likely produced this infant’s defect?
A. Chlordae tendineae
B. Crista terminalis
C. Endocardial cushion
D. Septum primum
E. Sinus venosus