Which pair of heart sounds constitutes the normal sounds S1 and S2, with S3 and S4 considered minor sounds?

Which pair of heart sounds constitutes the normal sounds S1 and S2, with S3 and S4 considered minor sounds?

• A. S1 and S2
• B. S2 and S3
• C. S1 and S3
• D. S3 and S4

Answer: (A)

Recognizing normal heart sounds versus extra sounds is the key idea. The normal pair comes from the closures of the heart valves: the first sound (the lub) is produced when the atrioventricular valves close at the start of ventricular systole, and the second sound (the dub) comes from the semilunar valves closing at the end of systole (beginning of diastole). These two sounds are the primary, expected sounds heard in a healthy heart. The other two sounds are additional or minor sounds that can appear in certain conditions: one occurs early in diastole with rapid ventricular filling and can be normal in youth but may indicate volume overload in older adults; the other occurs late in diastole from atrial contraction into a stiff ventricle and is associated with stiffening of the ventricle. In a healthy adult, S1 and S2 are the prominent, normal sounds, while S3 and S4 are not typically present.

Recognizing normal heart sounds versus extra sounds is the key idea. The normal pair comes from the closures of the heart valves: the first sound (the lub) is produced when the atrioventricular valves close at the start of ventricular systole, and the second sound (the dub) comes from the semilunar valves closing at the end of systole (beginning of diastole). These two sounds are the primary, expected sounds heard in a healthy heart. The other two sounds are additional or minor sounds that can appear in certain conditions: one occurs early in diastole with rapid ventricular filling and can be normal in youth but may indicate volume overload in older adults; the other occurs late in diastole from atrial contraction into a stiff ventricle and is associated with stiffening of the ventricle. In a healthy adult, S1 and S2 are the prominent, normal sounds, while S3 and S4 are not typically present.