During your cardiac assessment, you may appreciate extra heart sounds or heart murmurs when auscultating the chest. In general, murmurs can be differentiated from additional sounds, such as an S3 or S4, because of their longer duration, however there is much more to assessing murmurs and understanding their underlying causes. The best way to learn is to take advantage of listening to murmurs whenever possible! Let’s review some of the basics.

Characteristics of Murmurs

Timing
The timing of murmurs is identified by when the murmur is heart in the cardiac cycle. Systolic murmurs are heard between S1 and S2; diastolic murmurs are heard between S2 and S1. They can be further characterized by how long they ‘occupy’ systole or diastole. Continuous murmurs begin in systole and continues to diastole without interruption.

Intensity
Different grading systems are used to describe the intensity, or loudness, of murmurs; a six-point scale is used to grade systolic murmurs and a four-point scale is used to grade diastolic murmurs. In general, the grading is expressed as a fraction, with the numerator representing the intensity at its loudest and the denominator being 4 or 6, depending on the scale used.

The intensity of murmurs can be decreased due to obesity, emphysema, and pericardial effusion.

Shape
The shape or configuration of a murmur refers to its intensity over time. Crescendo is used to describe murmurs that increase or grow louder. Decrescendo refers to those that soften or decrease in intensity. Crescendo-decrescendo means the murmur increases and then decreases. Plateau means unchanged in intensity.

Location & Radiation
When describing the location of a murmur, it’s important to identify where the murmur is best heard, which is typically the site where it originates. When thinking about radiation of the murmur, ask “Where else is the murmur heard?” In some instances, it can be heard over the left scapula or in the axilla.

Pitch & Quality
Murmurs can be described as high-pitched, medium-pitched or low-pitched. The quality can be described as blowing, harsh, scratching, rumbling or musical.

References:
Bickley, L. S., Szilagyi, P. G., Hoffman, R. M., & Soriano, R. P. (2021). Bate’s Guide to Physical Examination and History Taking (13th ed.). Wolters Kluwer Health: Philadelphia.

Meyer, T. (2020, February 4). Auscultation of cardiac murmurs in adults. UpToDate. https://www.uptodate.com/contents/auscultation-of-cardiac-murmurs-in-adults

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