A 4-year-old is brought to the pediatrician for a well-child examination. A murmur is auscultated. A diagram showing oxygen tension at various anatomic locations is depicted.
Failure of which of the following is the most likely explanation for these findings?
Closure of the ductus arteriosus
Closure of the ductus venosus
Closure of the foramen ovale
Fusion of interventricular septum with endocardial cushions
Myxomatous degeneration
