Functional murmur

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.
• 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 or thyrotoxicosis.

Prognosis

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