A functional murmur is a heart murmur

Heart murmur

Murmurs are extra heart sounds that are produced as a result of turbulent blood flow that is sufficient to produce audible noise. Most murmurs can only be heard with the assistance of a stethoscope ....

 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.

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 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 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

Child

Biologically, a child is generally a human between the stages of birth and puberty. Some vernacular definitions of a child include the fetus, as being an unborn child. The legal definition of "child" generally refers to a minor, otherwise known as a person younger than the age of majority...

 grows. ECG and Chest XRAY are normal.

Types, description and DDx

Benign Paediatric Heart Murmurs

Name	Location	DDx Differential diagnosis A differential diagnosis is a systematic diagnostic method used to identify the presence of an entity where multiple alternatives are possible , and may also refer to any of the included candidate alternatives A differential diagnosis (sometimes abbreviated DDx, ddx, DD, D/Dx, or ΔΔ) is a...
Still's murmur Still's murmur Still's murmur is a form of benign paediatric heart murmur.It is named for Sir George Frederick Still....	inferior aspect of LLSB (lower left sternal border), systolic ejection sound, vibratory/musical quality	subaortic stenosis, small VSD Ventricular septal defect A ventricular septal defect is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart.The ventricular septum consists of an inferior muscular and superior membranous portion and is extensively innervated with conducting cardiomyocytes.The membranous...
Pulmonary ejection	superior aspect of LLSB, ejection sound	Pulmonary stenosis, atrial septal defect Atrial septal defect Atrial septal defect is a form of congenital heart defect that enables blood flow between the left and right atria via the interatrial septum. The interatrial septum is the tissue that divides the right and left atria...
Venous hum Venous hum Venous hum is a benign phenomenon. At rest, 20% of the cardiac output flows to the brain via the internal carotid and vertebral arteries. This drains via the internal jugular veins. The flow of blood can cause the vein walls to vibrate creating a humming noise which can be heard by the subject...	Infraclavicular throughout the cardiac cycle Cardiac cycle The cardiac cycle is a term referring to all or any of the events related to the flow or blood pressure that occurs from the beginning of one heartbeat to the beginning of the next. The frequency of the cardiac cycle is described by the heart rate. Each beat of the heart involves five major stages...  (right side > left side), diminishes with jugular vein palpation or neck turning	PDA Patent ductus arteriosus Patent ductus arteriosus is a congenital disorder in the heart wherein a neonate's ductus arteriosus fails to close after birth. Early symptoms are uncommon, but in the first year of life include increased work of breathing and poor weight gain...
Supraclavicular arterial bruit (Systemic Flow Murmur)	Above clavicle Clavicle In human anatomy, the clavicle or collar bone is a long bone of short length that serves as a strut between the scapula and the sternum. It is the only long bone in body that lies horizontally... s	aortic stenosis, bicuspid aortic valve Bicuspid aortic valve A bicuspid aortic valve is most commonly a congenital condition of the aortic valve where two of the aortic valvular leaflets fuse during development resulting in a valve that is bicuspid instead of the normal tricuspid configuration. Normally the only cardiac valve that is bicuspid is the mitral...
Peripheral pulmonary stenosis (Pulmonary flow murmur)	High-pitch with radiation to back and armpit	PDA Patent ductus arteriosus Patent ductus arteriosus is a congenital disorder in the heart wherein a neonate's ductus arteriosus fails to close after birth. Early symptoms are uncommon, but in the first year of life include increased work of breathing and poor weight gain... , pulmonary stenosis

External links

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