A functional murmur (innocent murmur, physiologic murmur) is a

heart murmur Heart murmurs are unique heart sounds produced when blood flows across a heart valve or blood vessel. This occurs when turbulent blood flow creates a sound loud enough to hear with a stethoscope. Turbulent blood flow is not smooth. The sound d ...

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.

Benign pediatric heart murmur

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

Presentation

*Soft, less than 3/6 in intensity (although note that even when structural heart disease is present, intensity does not predict severity.) *Often position-dependent. Murmurs heard while supine and may disappear when upright or sitting.Thomas Biancaniello
Innocent Murmurs
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Circulation Circulation may refer to: Science and technology * Atmospheric circulation, the large-scale movement of air * Circulation (physics), the path integral of the fluid velocity around a closed curve in a fluid flow field * Circulatory system, a bio ...

''. 2005; 111: e20-e22. *Otherwise healthy individual, no concerns about growth, no symptoms of

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

such as dyspnea on exertion. (In infants, ask if the baby cries during feeding, becomes diaphoretic, or develops a rapid respiratory rate. In older children, this can be elucidated by asking whether or not the child can keep up with peers during play.) *Occurs during systole or continuously during both systole and diastole. (Murmurs occurring only during diastole are usually pathologic, but can also be heard during hyperdynamic states.) *Physiologic splitting of S2 (A2 and P2 components should only be resolvable during inspiration and should merge during expiration.) *No palpable thrill (A thrill is a vibration caused by turbulent blood flow.)

Diagnosis

Types, and DDx

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

anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, ...

thyrotoxicosis Hyperthyroidism is the condition that occurs due to excessive production of thyroid hormones by the thyroid gland. Thyrotoxicosis is the condition that occurs due to excessive thyroid hormone of any cause and therefore includes hyperthyroidis ...

Prognosis

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

References

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

External links

Heart Murmurs in Pediatric Patients: When Do You Refer?
- AAFP {{Circulatory and respiratory system symptoms and signs Heart murmurs Pediatrics