Heart Sounds Tutor
Nurses often auscultate the heart but may have difficulty identifying the sounds they hear. The purpose of this tutor is to describe the basic characteristics of heart sounds and what they represent to cardiac function.
Auscultation of the Heart
There are four major functional areas of auscultation of the heart. They are named for the valve that they best assess.
|
Area |
Location |
|
Abnormality |
|
Aortic |
2nd ICS
R sternal border |
 |
Aortic Stenosis
S2 is loudest here |
|
Pulmonic |
2nd ICS
L sternal border |
 |
Pulmonary stenosis or regurgitation |
|
Tricuspid |
L lower sternal border |
 |
Tricuspid stenosis |
|
Mitral |
5th ICS |
 |
Mitral stenosis or regurgitation
S1 is loudest here |
Normal Heart Sounds
Normal heart sounds are produced by closure of the valves of the heart. Flow through the valves will affect the sound the valve makes. Thus, in situations of increased flow (exercise for example) the intensity of the heart sounds will be increased. In situations of low flow (shock for example) the intensity of the heart sounds will be decreased.
S1: The S1 sound is normally the first heart sound heard. See the diagram below for the location of S1 during the cardiac cycle. The S1 is best heard in the mitral area, and corresponds to closure of the mitral and tricuspid (AV) valves. A normal S1 is low-pitched and of longer duration than S2.
S2: The S2 sound is normally the second sound heard. The S2 is best heard over the aortic area, and corresponds to closure of the pulmonic and aortic valves. A normal S2 is higher-pitched and of shorter duration than S1.
The flow from the ventricles is more forceful than the flow from the atria. Therefore, S2 will normally be the louder sound.
Abnormal Heart Sounds
S3: The S3 sound is heard immediately following S2, and is normal in children and adolescents, but usually disappears after age 30. When heard in adults, an S3 is called a “gallop” and indicates left ventricular failure.
S4: The S4 sound is heard immediately before the S1, and may be present in infants and children. The S4 is produced with decreased compliance of the ventricle and may indicate myocardial infarction or shock.
Correlation with Clinical Condition
Assessment of heart sounds should always be correlated with the patient’s clinical condition. There are many factors that affect heart sounds and may produce alterations in normal sounds or abnormal sounds. These include: congenital abnormalities, previous cardiac disease, flow of blood through the heart, and patient age. Consider the following examples:
25 year-old diabetic patient who presents to the Emergency Department with diabetic ketoacidosis. On auscultation a S3 sound is heard. An S3 can indicate congestive heart failure, but in this case probably represents a normal finding.
79 year-old COPD patient in the hospital. On auscultation an S3 is heard. Patients with COPD are at risk for cardiac problems and this may represent early heart failure.
Heart sound auscultation is just one part of your assessment. Correlate it with the patient’s clinical condition, and presenting symptoms to best understand what your assessment means for this patient.
For more information on heart sounds, try these resources:
Auscultation Skills: Breath and Heart Sounds (Breathing & Heart Sounds)
The Auscultation Assistant