The Foley Family is caring for their youngest child, Justin, who is suffering from tetralogy of Fallot. Which of the following are defects associated with this congenital heart condition?
A. Aorta exits from the right ventricle, pulmonary artery exits from the left ventricle, and two noncommunicating circulations
B. Ventricular septal defect, overriding aorta, pulmonic stenosis (PS), and right ventricular hypertrophy
C. Coarctation of aorta, aortic valve stenosis, mitral valve stenosis, and patent ductus arteriosus
D. Tricuspid valve atresia, atrial septal defect, ventricular septal defect, and hypoplastic right ventricle
Correct Answer: B. Ventricular septal defect, overriding aorta, pulmonic stenosis (PS), and right ventricular hypertrophy
The defects associated with tetralogy of Fallot include ventricular septal defect, overriding aorta, pulmonic stenosis (PS), and right ventricular hypertrophy. The exact embryological process that contributes to the development of tetralogy of Fallot still is unknown, but an association that had been observed is an anterior and cephalad deviation of the infundibular septum that results in a misaligned ventricular septal defect, with an overriding aortic root causing a subsequent right ventricular outflow obstruction.
Option A: The aorta exiting from the right ventricle with no communication between the systemic and pulmonic circulation describes the defects associated with transposition of the great vessels. The degree of the overriding aorta usually varies and receives blood flow from both ventricles.
Option C: Coarctation of aorta and aortic and mitral valve stenosis are defects associated with tricuspid atresia. Severe coarctation of aorta, severe aortic valvular stenosis or atresia, and severe mitral valve stenosis or atresia are defects associated with hypoplastic left heart syndrome.
Option D: Also, the left ventricle, aortic valve, mitral valve, and ascending aorta usually are small or hypoplastic. Different factors can contribute to the right ventricular outflow obstruction, including the pulmonary valve that is usually bicuspid and stenotic, the hypoplastic pulmonary valve annulus, the deviation of the infundibular septum that causes a subvalvular obstruction, and the hypertrophy of the muscular bands in this region.