A high-pitched decrescendo murmur at the left upper sternal border that increases with inspiration is most consistent with which valvular lesion?

• A. Aortic stenosis
• B. Pulmonary regurgitation
• C. Tricuspid regurgitation
• D. Mitral valve prolapse

Answer: (B)

An early diastolic, high-pitched decrescendo murmur at the left upper sternal border that worsens with inspiration points to pulmonary regurgitation. The sound comes from backflow of blood from the pulmonary artery into the right ventricle during diastole. The inspiration effect makes sense because taking a breath increases venous return to the right heart, increasing the amount of regurgitated flow and thus the murmur.

This differs from other common murmurs: aortic stenosis is a systolic murmur heard at the right upper sternal border, mitral valve prolapse has a midsystolic click with a murmur, and tricuspid regurgitation is a holosystolic murmur best heard at the left lower sternal border that also varies with inspiration but occurs in systole, not diastole.