A benign pediatric heart murmur, also innocent heart murmur or innocent murmur, is an inconsequential sound that originates from the heart and/or cardiovascular system and is heard on cardiac auscultation. By definition, an innocent murmur is not significant in the long-term health of an individual that has it.

Characteristics

• 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 upright or sitting may disappear when lying supine.)
• Otherwise healthy individual, no concerns about growth, no symptoms of heart failure such as dyspnea on exertion. (In infants, ask if the baby tires 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 always pathologic.)
• 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.)

Prognosis

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

Types, description and DDx

Benign Paediatric Heart Murmurs

Name	Location	DDx
Still's murmur	inferior aspect of LLSB, systolic ejection sound, vibratory/musical quality	subaortic stenosis, small VSD
Pulmonary ejection	superior aspect of LLSB, ejection sound	Pulmonary stenosis, atrial septal defect
Venous hum	Infraclavicular throughout the cardiac cycle (right side > left side), diminishes with jugular vein palpation or neck turning	PDA
Supraclavicular arterial bruit	Above clavicles	aortic stenosis, bicuspid aortic valve
Peripheral pulmonary stenosis	low-pitch with radiation to back and armpit	PDA, pulmonary stenosis

LLSB = lower left sternal border

See also

• Heart murmur
• Precordial examination
• Ventricular septal defect

External links

• Heart Murmurs in Pediatric Patients: When Do You Refer? - AAFP