Critical Care Paramedic Practice Exam

Tetralogy of Fallot is characterized by the presence of four specific cardiac anomalies, which is why the correct choice identifies it as a right to left shunt consisting of those four defects. These defects include ventricular septal defect (VSD), pulmonary outflow obstruction (usually due to pulmonary stenosis), right ventricular hypertrophy (RVH), and an aortic override, where the aorta is positioned directly over the ventricular septal defect and straddles both ventricles.

In this condition, the right-to-left shunt occurs because the pressure in the right ventricle exceeds that in the left ventricle, allowing deoxygenated blood to flow into systemic circulation rather than going through the lungs for oxygenation. This leads to cyanosis, particularly during exertion or events like crying, where increased demands on the heart create greater shunting effects. Understanding the four key defects that define Tetralogy of Fallot is crucial for accurate diagnosis and management of the condition.