A 5-year-old youngster is brought to the office by his parents for cyanosis examination with no effort. The youngster has experienced instances of "turning blue" that began in infancy and are now becoming more regular. Throughout the episodes, the youngster squats because it makes him "feel better." The boy's family recently emigrated to the United States, and he had never received a medical examination previous to this visit. A significant right ventricular impulse and a loud systolic murmur are discovered during physical examination. Which of the following embryological events is the most likely cause of this patient's condition?

Question

Quizplus · Accepted Answer

Eductional Objective: Tetralogy of Fallot is caused by anterior and cephalad displacement of the infundibular septum during embryologic development, culminating in a ventricular septal defect (VSD) with an overriding aorta. As a result of the right ventricular outflow blockage (leading in a systolic murmur), the patient squats to raise peripheral systemic vascular resistance (afterload) and decrease right-to-left shunting across the VSD.

A 5-Year-Old Youngster Is Brought to the Office by His