Two different sounds made by the heart as it beats.
Any of four distinct sounds produced within the heart during its normal cycle of contraction and relaxation and heard with a stethoscope placed on the chest over the heart. The first sound (a dull, prolonged lub) is caused by closure of the valves between the atria and ventricles and marks the beginning of ventricular contraction; the second (a short sharp dub) occurs with closing of the semilunar valves as the ventricle begins to relax; the third (a weak, dull sound usually not heard except in heart failure) occurs as the ventricles fill with blood during their relaxed phase; the fourth (not usually heard in normal hearts) occurs as the atria contract. Changes in the characteristic sounds usually indicate abnormalities in heart structure or function and are important diagnostic aids.
The two sounds “lubb” and “dupp” heard when listening to the heart with a stethoscope. They arise from valve closure and muscular structures in the heart and are technically called S1 and S2. Third and fourth heart sounds may be present in some heart diseases.
The heart produces distinct sounds during each heartbeat. Within the heart cycle, two primary heart sounds can be clearly heard through a stethoscope. The first sound is akin to a “lubb” and results from the closure of the tricuspid and mitral valves at the exits of the atria (upper heart chambers) when the ventricles (lower heart chambers) start contracting to pump blood out of the heart. The second sound is a higher-pitched “dupp” and is caused by the closure of the pulmonary and aortic valves at the exits of the ventricles when the ventricles complete their contraction.
Unusual heart sounds can indicate different disorders. For instance, high-pitched sounds or “clicks” may arise from the sudden stoppage of valve opening, which can be present in individuals with specific heart valve abnormalities. Heart murmurs are abnormal sounds resulting from turbulent blood flow and may be attributed to heart valve defects or congenital heart disease.
Noises detected above the cardiac region. The initial sound, characterized as a dull and prolonged “lubb,” results from ventricular contraction. The subsequent sound, sharp and brief, resembling “dup,” arises from the closure of the heart valves. These sounds are also referred to as cardiac sounds.