All murmurs are high-pitched except those of which valves?

The correct conclusion identifies that all murmurs are high-pitched except for those originating from the mitral and tricuspid valves. This is primarily due to the unique anatomical and functional characteristics of these valves.

Murmurs associated with the mitral valve, particularly those caused by conditions such as mitral regurgitation or stenosis, tend to be lower in pitch. This lower pitch arises from the greater volume of blood flow across the valve and the pressures involved in the left atrium and ventricle. Similarly, tricuspid murmurs, which might be produced by tricuspid regurgitation or stenosis, are also characterized by a lower frequency sound for analogous reasons involving the right side of the heart.

In contrast, murmurs from the aortic and pulmonic valves are typically high-pitched due to the high pressures associated with the left ventricle and the pulmonary artery, which contribute to a distinct sound when blood flows through these areas. The high-velocity blood flow through the aortic and pulmonic valves results in higher frequency sounds that are perceived as high-pitched murmurs.

Understanding the physiology of cardiac function and valve mechanics aids in recognizing these variations in murmur characteristics, which is critical for assessment in critical care settings