A 4-year-old boy has a 2/6 holosystolic murmur auscultated at the left sternal border. Cardiac catheterization shows O2 saturation as follows:
Left atrium: 99%
Left ventricle: 99%
Right atrium: 73%
Right ventricle: 84%
Vena cava: 73%
Which of the following best explains these findings?
Failure of closure of the ductus arteriosus
Failure of closure of the foramen ovale
Failure of fusion of the endocardial cushions with the interventricular septum
Failure of resorption of the septum primum
Failure of vena caval rotation about the atria
—
Cut-to-the-chase Answer (0:25):
—
HY USMLE Answer (3:51):
