Professional and Linguistic Assessments Board (PLAB) Practice Exam

Which heart defect is associated with a pansystolic murmur in infants?

1. Aortic stenosis

2. Mitral regurgitation

3. Tricuspid regurgitation

4. Ventricular septal defect

The correct answer is: Mitral regurgitation

The association of a pansystolic murmur in infants is most characteristic of ventricular septal defect (VSD). VSD is a congenital heart defect where there is an opening in the ventricular septum, allowing blood to flow from the left ventricle to the right ventricle during systole. This left-to-right shunt leads to increased blood flow through the pulmonary circulation and a corresponding murmur that is typically heard throughout systole, thus classifying it as a pansystolic murmur. In contrast, aortic stenosis, mitral regurgitation, and tricuspid regurgitation, while they can produce murmurs, generally do not present in the same manner in infants. Aortic stenosis typically generates a systolic ejection murmur, often described as a "crescendo-decrescendo," rather than pansystolic. Mitral regurgitation can produce a holosystolic murmur, but it's less common in infants compared to the classic presentation of VSD. Tricuspid regurgitation would usually present with a systolic murmur at the left lower sternal border but is also not as commonly noted in the infant population. Therefore, the correct association of a pansystolic murmur with ventricular