Functional murmur

A functional murmur (innocent murmur, physiologic murmur) is a heart murmur that is primarily due to physiologic conditions outside the heart, as opposed to structural defects in the heart itself.

Serious conditions can arise even in the absence of a primary heart defect, and it is possible for peripheral conditions to generate abnormalities in the heart. Therefore, caution should be applied to use of the terms "innocent" or "benign" in this context.

Use of the term dates to the mid 19th century.

Functional murmurs are an important consideration in the precordial examination of an infant or child.

Innocent murmurs are inconsequential and usually disappear as the child grows. ECG and Chest XRAY are normal.

In the adult, hyperdynamic circulation of the blood may also produce a functional murmur, such as in anemia or thyrotoxicosis.

5. Circulation 2005: Innocent Murmurs http://circ.ahajournals.org/cgi/content/full/111/3/e20

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