Professional and Linguistic Assessments Board (PLAB) Practice Exam

Which congenital heart defect is characterized by an ejection murmur?

1. Transposition of the great vessels

2. Tetralogy of Fallot

3. Truncus arteriosus

4. Ventricular septal defect

The correct answer is: Tetralogy of Fallot

Tetralogy of Fallot is characterized by a combination of four cardiac anomalies: ventricular septal defect (VSD), right ventricular outflow tract obstruction (often due to pulmonary stenosis), right ventricular hypertrophy, and an overriding aorta. The presence of a ventricular septal defect allows blood to shunt from the left ventricle to the right ventricle, but the right ventricle faces the obstruction, leading to increased right ventricular pressure. The ejection murmur in Tetralogy of Fallot is primarily due to the turbulence of blood flow as it exits the right ventricle through the narrowed outflow tract, resulting in a characteristic systolic murmur that can be heard best at the left upper sternal border. This murmur is indicative of the right ventricular pressure overload and the dynamic behavior of blood flow in this condition. In contrast, other congenital heart defects have different auscultatory findings: Transposition of the great vessels typically presents with a single loud second heart sound and may not have prominent murmurs associated with ejection; truncus arteriosus often features a continuous murmur due to the presence of both a VSD and significant pulmonary blood flow; and a ventricular septal defect commonly produces a holosyst