Tricuspid regurgitation in intravenous drug users is best described as which murmur characteristic?

• A. Holosystolic murmur that diminishes with inspiration
• B. Holosystolic murmur that increases with inspiration
• C. Diastolic murmur
• D. Continuous murmur

Answer: (B)

The key idea is how right-sided heart murmurs behave with respiration. Tricuspid regurgitation flows back into the right atrium during systole, and inspiration increases venous return to the right heart. That extra blood makes the regurgitant jet louder, so the murmur grows louder with inspiration—a phenomenon known as Carvallo’s sign.

In IV drug users, tricuspid valve endocarditis is a common cause of tricuspid regurgitation, so this scenario fits TR well. The murmur itself is holosystolic and best heard along the left lower sternal border, and its intensity increases with inspiration.

The other options don’t fit: a diastolic murmur isn’t characteristic of TR, and a continuous murmur suggests something like a PDA or other vascular shunt rather than TR. A holosystolic murmur that diminishes with inspiration would be more typical of a left-sided murmur, not TR.