How does the sound of mitral valve prolapse (MVP) present clinically?

Mitral valve prolapse (MVP) is characterized by the abnormal displacement of one or both of the mitral valve leaflets into the left atrium during systole. Clinically, this is commonly manifested as a mid-systolic click, which occurs when the prolapsing leaflet suddenly becomes taut during ventricular contraction. The click is often followed by a late systolic murmur, which results from the regurgitation of blood into the left atrium due to the inability of the valve to close properly.

The continuous nature of the murmur associated with MVP is important to note, as it may change in intensity with maneuvers that alter venous return or peripheral vascular resistance, such as standing or squatting. In contrast to other options, which describe different types of murmurs, the presence of the mid-systolic click is a hallmark find that helps differentiate MVP from other valvular disorders.