Pearls of Knowledge: Four Heart Sounds

Heart Sounds: Recognizing the “Four” Which are Possible

Pearls of Knowledge          © BrainyNurses.com

In listening to the heart, a systematic approach is important. And remember, the more you listen, the better your skills will become. 😊 In acute conditions, listening to heart sounds is very important on presentation, and then with subsequent assessments. If heart sounds change, it generally signifies a deterioration in condition.

 Be sure to determine the following with assessment.

• The strength of the heart sounds.
• The heart sounds heard (S1, S2, S3, S4).
• If systolic or diastolic murmurs are present.
• If a friction rub is present.

Listening to the four possible heart sounds

As the valves close, S1 and S2 are produced. 

• S1 indicates closure of the mitral and tricuspid valves, is heard the loudest in those areas of the heart and occurs during systole. 

• S2 indicates closure of the aortic and pulmonic valves, is heard the loudest in those areas of the heart and occurs at the end of systole and beginning of diastole. 

• If there is stenosis in the valve, a click may be heard as the valve snaps open. 

At times, there are more than two sounds heard. So, as you were listening to “Lub, Dub, Lub, Dub”, you hear “other” sounds.

S3 (gallop)

• Caused by turbulence on ventricular filling.
• Indicates heart failure and will be heard before crackles develop.
• Heard in systolic dysfunction which is a problem with contraction.
• An S3 may be normal in children and those under the age of 40 years. 

S4 (gallop)

• Produced when the atria contract.
• Heard in several conditions, including myocardial ischemia or infarction.
• Will also be heard in hypertension, ventricular hypertrophy, AV blocks, and severe aortic or pulmonic stenosis. 
• It may also be heard in diastolic dysfunction, which is a problem with filling.
• It will not be heard in atrial fibrillation due to the lack of coordinated atrial contraction. 

Some medical professionals feel like they want to “listen” to audio recordings of heart sounds. While this may be beneficial, it is difficult to translate what you heard on a demo into clinical practice.

Instead, try listening for “sounds” in words you can use to describe the heart sounds.