Heart Sounds And Murmurs

The beating heart produces characteristic sounds (tones) that can be heard by placing your ear to your chest or using a stethoscope. In most healthy people, with each contraction of the heart, two sounds occur, one of which is low, not very loud, but long-lasting. This sound is caused partly by the closing of the tricuspid and bicuspid valves, and partly by the contraction of the ventricular muscle (all muscles contracting produce sound).

The first sound, marking the beginning of ventricular systole, is soon followed by a second, which is higher, louder and shorter than the first. It is caused by the closure of the semilunar valves and marks the end of ventricular systole. Based on the nature of these two tones, the doctor judges the condition of the valves.

If the semilunar valves are damaged, then instead of the second tone a soft hissing noise is heard. Such a noise may be caused by syphilis, rheumatism, or any other disease leading to damage to the valves, as a result of which the valves do not close tightly enough and blood can flow from the arteries back into the ventricles during diastole. Damage to the bicuspid or tricuspid valve affects the nature of the first heart sound.