What does a holistic murmur at the left sternal border suggest?

A holosystolic murmur, often associated with regurgitation, typically occurs when blood flows back through the heart during the contraction phase. When this type of murmur is heard at the left sternal border, it is commonly associated with tricuspid valve involvement. The tricuspid valve is located between the right atrium and right ventricle, and its dysfunction can lead to backflow into the right atrium, especially during ventricular contraction, producing a holosystolic murmur that is best heard at the left sternal border.

This specific location is crucial for identifying the involvement of the tricuspid valve. While murmurs from other valves (like the aortic, mitral, or pulmonic valve) can also occur, their characteristics and locations differ significantly. For example, aortic valve murmurs generally arise from the right second intercostal space, mitral valve murmurs are typically heard at the apex of the heart, and pulmonic valve murmurs are often audible over the left second intercostal space. Thus, the distinct sound and its location are key indicators of tricuspid valve dysfunction.