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 di ...
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
'' Circulation''. 2005; 111: e20-e22.
*Otherwise healthy individual, no concerns about growth, no symptoms of
heart failure 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, t ...
or
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 hyperthyroidism. ...
.
Prognosis
Innocent murmurs are inconsequential
and usually disappear as the
child grows. ECG and Chest XRAY are normal.
See also
*
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 di ...
*
Precordial examination
In medicine, the cardiac examination, also precordial exam, is performed as part of a physical examination, or when a patient presents with chest pain suggestive of a cardiovascular pathology. It would typically be modified depending on the indi ...
*
Ventricular septal defect
A ventricular septal defect (VSD) is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart. The extent of the opening may vary from pin size to complete absence of the ventricular septum, creating one ...
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
The American Academy of Family Physicians (AAFP) was founded in 1947 to promote and maintain high-quality standards for family medicine, an offshoot of the classical general practitioner. It is headquartered in Leawood, Kansas.
AAFP is one of ...
{{Circulatory and respiratory system symptoms and signs
Heart murmurs
Pediatrics