To clinicians heart sounds provide important information about the normal function of the heart and assist in diagnosing cardiac abnormalities. Abnormal heart sounds are called murmurs, and certain murmurs are important indicators of specific cardiac abnormalities. For example, an incompetent value is a valve that leaks significantly. After closure of an incompetent valve, blood flows through it in a reverse direction. The movement of blood in a direction opposite to normal results in turbulence, which causes a gurgling or swishing sound immediately after closure of the valve. An incompetent tricuspid valve or bicuspid valve exhibits a swish sound immediately after the first heart sound, and the first heart sound can be muffled. An incompetent aortic or pulmonary semilunar valve results in a swish sound immediately after the second heart sound.

Stenosed valves have an abnormally narrow opening and also produce abnormal heart sounds. Blood flows through stenosed valves in a very turbulent fashion., producing a rushing sound before the value closes. Therefore, a stenosed atrioventricular valve results in a rushing sound immediately before the first heart sound, and a stenosed semilunar valve results in a rushing sound immediately before the second heart sound.

Inflammation of the heart valves, resulting from conditions such as rheumatic fever, can cause valves to become either incompetent or stenosed. In addition, myocardial infarctions that cause papillary muscles to become nonfunctional can cause bicuspid or tricuspid valves to be incompetent.

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