Heart sounds

Heart sounds are acoustic vibrations produced by cardiac activity and blood flow. Their timing, duration, and character can help assess heart function and detect disease.

S1 heart sound: The first heart sound, produced mainly by closure of the mitral and tricuspid valves at the start of ventricular systole. Its onset marks the beginning of the main sound sequence heard during each heartbeat.
Cardiac auscultation: The examination of heart sounds and murmurs by listening to the chest, usually with a stethoscope. It is the clinical method through which heart sounds are commonly assessed.
Aortic stenosis: Narrowing of the aortic valve that obstructs blood flow from the left ventricle into the aorta. It can alter S2 and produce a characteristic systolic murmur alongside normal heart sounds.
Physiologic splitting of S2: The normal separation of aortic and pulmonary valve closure sounds during inspiration. It demonstrates how breathing changes the timing of a normal heart sound.
Electronic stethoscope: A stethoscope that electronically amplifies or processes body sounds. It can make faint heart sounds easier to hear and record.
S2 heart sound: The second heart sound, produced by closure of the aortic and pulmonary valves near the end of ventricular systole. Its components mark the transition from ventricular ejection to relaxation.
Heart valve: A structure that directs blood through the heart by opening and closing between chambers or vessels. Valve motion generates the principal sounds heard in a normal heartbeat.
Mitral regurgitation: Backward flow from the left ventricle into the left atrium through an incompletely closed mitral valve. Its systolic murmur is interpreted in relation to S1 and S2.
Fixed splitting of S2: A persistent separation of the aortic and pulmonary components of S2 that changes little with breathing. Its invariant timing is a classic clue to an atrial septal defect.
Doppler echocardiography: Ultrasound imaging that measures blood-flow direction and velocity within the heart and vessels. It tests whether an acoustic finding corresponds to abnormal valve flow.

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René LaennecRelated: Auscultation extended the same listening approach from the lungs to the heart.