heart sounds

the sounds heard on the surface of the chest in the heart region; they are amplified by and heard more distinctly through a stethoscope. They are caused by the vibrations generated during the normal cardiac cycle and may be produced by muscular action, valvular actions, motion of the heart, or blood passing through the heart.

The first heart sound (S₁) is heard as a firm but dull “lubb” sound. It consists of four components: a low-frequency, indistinct vibration caused by ventricular contraction; a louder sound of higher frequency caused by closure of the mitral and tricuspid valves; a vibration caused by opening of the semilunar valves and early ejection of blood from the ventricles; and a low-pitched vibration produced by rapid ejection.

The second heart sound (S₂) is shorter and higher pitched than the first, is heard as a “dupp” and is produced by closure of the aortic and pulmonary valves.

The third heart sound (S₃) is very faint and is caused by blood rushing into the ventricles. It can be heard in most normal persons between the ages of 10 and 20 years.

The fourth heart sound (S₄) is rarely audible in a normal heart but can be demonstrated on graphic records. It is short and of low frequency and intensity, and is caused by atrial contraction. The vibrations arise from atrial muscle and from blood flow into, and distention of, the ventricles.

Abnormalities in Heart Sounds. Decreased compliance of a ventricle is characterized by a gallop or triple rhythm. Accentuation of the third heart sound (protodiastolic or ventricular gallop) is caused by the filling of a poorly compliant ventricle with blood under high venous pressure. A presystolic or atrial gallop is an accentuated fourth heart sound and is also caused by blood filling a poorly compliant ventricle. Merging of the third and fourth heart sounds is called a mesodiastolic or summation gallop. A very rare abnormality in which four heart sounds are heard distinctly is called a “locomotive” rhythm.

Heart Murmurs are sounds other than the normal heart sounds emanating from the heart region. They are often heard as blowing or hissing sounds as blood leaks back through diseased and malfunctioning valves or as blood is pushed through narrowed or stenotic valve orifices.

Precordial locations for cardiac palpation and auscultation of heart sounds. Closure of the mitral and tricuspid valves produces the S₁ heart sound; closure of the pulmonic and aortic (semilunar) valves produces the S₂ sound. From Polaski and Tatro, 1996.

heart sounds

the noise made by muscle contraction and the closure of the heart valves during the cardiac cycle. See: first heart sound, second heart sound, third heart sound, fourth heart sound.

Synonym(s): cardiac sound, heart tones

Farlex Partner Medical Dictionary © Farlex 2012

heart sounds

The sounds heard with a STETHOSCOPE applied over the heart. The most prominent sounds are caused by the closure of the heart valves. Heart abnormalities, especially valve disorders, cause additional sounds, called MURMURS. The timing and characteristics of these give much information about the state of the heart.

Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

heart sounds

(hahrt sowndz)

Noises made by muscle contraction and closure of heart valves during cardiac cycle.

Medical Dictionary for the Dental Professions © Farlex 2012

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References in periodicals archive

Bentley, "A robust heart sound segmentation and classification algorithm using wavelet decomposition and spectrogram", Workshop Classifying Heart Sounds, 2012.

Automatic Detection of Heartbeats in Heart Sound Signals Using Deep Convolutional Neural Networks

Heart sound signal can be considered as a periodic type noise signal since its location can be detected easily by any of linear time-frequency signal representations.

HEART SOUND LOCALIZATION AND REDUCTION IN TRACHEAL SOUNDS BY GABOR TIME-FREQUENCY MASKING

It should be noted that the heart sounds are not perfectly periodic due to the heart rate variability (HRV).

Fetal Heart Rate Monitoring from Phonocardiograph Signal Using Repetition Frequency of Heart Sounds

Moreover, the obtained results indicate that the shape related approaches are valuable for further improvements in the identification of the heart sounds.

Identification of S1 and S2 Heart Sound Patterns Based on Fractal Theory and Shape Context

In order to perform the long-term monitoring of cardiac activity (in both adults and fetuses during their intrauterine growth), it is more preferable to record phonocardiograms within a low-frequency band (40-90 Hz), which allows avoiding the overlapping of breath sounds with heart sounds down to the limit.

Short review of devices for detection of human breath sounds and heart tones

Listening to heart sounds is also used in monitoring for arrhythmia and diagnosing heart disease.2-4 However, traditional chest auscultation can be impossible depending on surgery, and extraneous noise can occur due to body movement.

The correlation between the first heart sound and cardiac output as measured by using digital esophageal stethoscope under anaesthesia

An adaptive filter with "Augmented ECG" as a reference signal was applied to filter out heart sounds from lung sounds in Iyer et al.

Performance evaluation of heart sound cancellation in FPGA hardware implementation for electronic stethoscope

The ability to label normal and abnormal heart sounds doubled; interpretation of normal and abnormal lung sounds improved by 50 percent; and bowel sounds interpretation improved threefold, demonstrating the effect of an adult-oriented, creative, yet practical method for teaching auscultation.

Looking is not seeing and listening is not hearing: effect of an intervention to enhance auditory skills of graduate-entry nursing students

"These human patient simulators have a full set of vital sign: heart sounds, breath sound, mouth sounds, pupillary reactions They breathe, they talk, their eyes are open, their level of consciousness changes."

Nurses expanding education with simulators

Additionally, a nested study on 34 patients to evaluate the accuracy and feasibility of transmission of echo pictures and heart sounds to Amrita Institute of Medical Sciences, Kochi via satellite using Indian Satellite Research Organization's network was also carried out.

Establishment of cardiovascular disease surveillance among the Adivasi population of Wayanad district

Kergaradec, who was a friend of Laennac--the inventor of the stethoscope--was the first doctor to use the stethoscope for auscultation of the fetal heart sounds. He thought he would hear the noise of water inside the uterus of a pregnant woman and be able to identify the position of the placenta.

Auscultation--the action of listening

During a routine examination, my doctor detected an abnormality in my heart sounds. He ordered an analysis of my blood and referred me to a cardiologist.

Longtime blood donor frustrated by bureaucratic rules