Extra heart sounds: Can you hear what I hear?

When performing a cardiovascular assessment, auscultation of heart sounds is a crucial element of the examination. Each sound has different characteristics, including timing and intensity. Read on to search out out more!

Heart cycle

A cardiac cycle starts from the start of 1 heartbeat to the start of the following heartbeat. Systole is a contraction that pushes blood out of the ventricles. Blood from the proper ventricle flows through the pulmonary valve to the lungs, while blood from the left ventricle flows through the aortic valve into the body. During systole, the tricuspid valve is closed, which prevents blood from flowing back from the proper ventricle into the proper atrium. Similarly, the mitral valve is closed, stopping blood from flowing back from the left ventricle into the left atrium. This closure of the mitral and tricuspid valves produces the S1 heart sound.

As the blood leaves the ventricles, the pressure within the ventricle decreases. During diastole, the tricuspid and mitral valves open to permit blood to flow into the ventricles, while the pulmonary and aortic valves close to forestall reflux from the pulmonary vein and aorta, respectively. This closure of the pulmonary and aortic valves produces the S2 heart sound.

Splits (S1 Split, S2 Split)

S1 splitting occurs when the sooner mitral closure and the later tricuspid closure sound separate. This could also be a standard finding. During exhalation, the aortic and pulmonary valves close almost concurrently, producing a single S2 sound. S2 splitting sometimes occurs during inspiration when the pulmonary valve barely delays its closure. S2 division may be a standard finding.

Gallops (S3, S4)

Sometimes after S2, an S3 gallop is heard resulting from slowing of blood flow within the ventricular wall. This could also be a standard occurrence in children, younger adults and athletes. However, in older people it is taken into account pathological and will indicate heart failure.

The heart sound S4 will probably be heard immediately before S1 of the following beat. If present, it might suggest ventricular stiffness and will be seen in individuals with hypertension or acute myocardial infarction. This could also be a standard phenomenon in athletes.

Opening the latches

When the mitral valve opens, if the valve leaflets are blocked, it’s possible you’ll hear a clicking sound because it opens. This will be heard just after S2 and will indicate mitral valve stenosis.

Crampy clicks

A clicking sound heard during systole may indicate mitral valve prolapse.

Remember

• When documenting the separated S1 and S2 sounds, it is vital to find out at what point within the respiratory cycle the sound is heard.
• In the elderly, S3 and S4 heart sounds needs to be reported to the responsible physician.
• Systolic clicks are essentially the most common additional heart sound.

Bickley, L. S., Szilagyi, P. G., Hoffman, R. M., & Soriano, R. P. (2021). Bate’s guide to physical examination and interviewing (thirteenth ed.). Wolters Kluwer Health: Philadelphia.