What are considered normal heart sounds?

Normal heart sounds are primarily identified as S1 and S2. S1, often described as a "lub," is created by the closure of the atrioventricular valves at the beginning of ventricular contraction (systole). S2, referred to as "dup," occurs when the semilunar valves close at the end of ventricular contraction and the start of diastole. Together, these two sounds indicate a healthy functioning heart, with S1 typically being louder and lower in pitch compared to the higher-pitched S2.

S3 and S4 sounds can sometimes be heard in specific contexts, such as in certain age groups or pathological states, but they are not considered "normal" in all individuals. While S3 may be heard in young athletes or during pregnancy, it can also indicate heart failure in older adults. S4 is often associated with conditions like hypertension or reduced ventricular compliance.

Other sounds like clicks and murmurs indicate abnormalities in heart function, often signaling valvular issues or turbulent blood flow, which are not part of the normal heart sound profile. Similarly, gallops and rubs suggest underlying pathologies that require further investigation and are not typical of normal heart function.