Which heart sound is commonly heard in mitral stenosis?

In mitral stenosis, the characteristic heart sound that is commonly heard is the opening snap. This sound occurs due to the abrupt halting of the thickened mitral valve leaflets as they open during diastole. The restriction of blood flow through a narrowed valve results in this distinctive sound, which occurs shortly after the second heart sound (S2). The timing and quality of the opening snap can help clinch the diagnosis of mitral stenosis, as it reflects the degree of stenosis present.

While the third heart sound and fourth heart sound can also be present in various heart conditions, they are not specific to mitral stenosis. The third heart sound often signifies rapid ventricular filling and can be seen in heart failure, while the fourth heart sound is indicative of increased resistance to filling, typically due to ventricular hypertrophy. A continuous murmur is typically associated with conditions such as patent ductus arteriosus or arteriovenous fistulae, but it is not a feature of mitral stenosis. Thus, the presence of an opening snap is a hallmark sign utilized by clinicians to identify mitral stenosis specifically.