11 Cardiac Murmurs


11 Cardiac Murmurs

A murmur can often be the most significant leading symptom of a congenital or acquired heart defect, but cardiac murmurs are also a harmless phenomenon in around half of all children.

11.1 Classification

Cardiac murmurs are classified as organic, functional, and innocent murmurs. The majority of murmurs auscultated in children are harmless functional or innocent heart murmurs. However, when investigating a murmur, an organic cause must be reliably excluded.

Organic murmurs

Organic heart murmurs are caused by congenital or acquired heart defects such as valvular stenosis or insufficiency or may be the result of pathological shunts. They are thus always pathological.

Functional murmurs

Functional heart murmurs are caused by extracardiac diseases that result in a change in blood flow or viscosity. These flow phenomena may be a result of fever, severe anemia, or hyperthyroidism, for example.

Innocent murmurs

Innocent heart murmurs are harmless, physiological acoustic phenomena that often occur in childhood (especially in young children) and are not pathological. The most important innocent heart murmurs are listed in Table 1.1 and Fig. 11.1.

Fig. 11.1 Location and characteristics of the most common innocent heart murmurs (from Driscoll DJ 2006).

11.2 Special Features of Heart Murmurs in Neonates and Young Infants

While innocent and functional murmurs are the most frequent in older children, organic murmurs indicating a congenital heart defect are found more often in neonates and young infants. Neonates or young infants in whom a murmur is detected should therefore be examined promptly by a pediatric cardiologist.

Additional symptoms

Additional symptoms aside from the murmur are particularly significant for the differential diagnosis.

The leading symptom of defects with reduced pulmonary perfusion, a right-to-left shunt, or parallel circulation of both systems is cyanosis.

Excessive pulmonary blood flow (e.g., as a result of a large left-to-right shunt) or severe left heart obstruction lead to heart failure (leading symptoms: tachypnea, tachycardia, hepatomegaly, pallor, failure to thrive, feeding problems, increased sweating).

Typical auscultation findings

Table 11.2 and Table 11.3 list typical findings of heart defects that can cause a heart murmur and other symptoms in neonates and young infants. Because of the significance for the differential diagnosis, congenital heart defects are categorized as those associated with cyanosis and those in which heart failure is the leading symptom.

Table 11.1 Questions that should be asked when investigating a heart murmur



Family history

Are there any family members with a congenital heart defect?

Increased risk of repetition

Gestational and perinatal history

Were there any infections during pregnancy (e.g., rubella)?

Increased risk for a congenital heart defect (e.g., pulmonary stenosis, PDA)

Did the mother take any medication or consume excessive alcohol during pregnancy?

Increased risk for a congenital heart defect (e.g., Ebstein anomaly if lithium was taken)

Did the mother have poorly controlled (gestational) diabetes during pregnancy?

Increased risk for a congenital heart defect (hypertrophic obstructive cardiomyopathy, VSD, TGA, etc.)

Was it a premature birth?

Increased risk for PDA

Personal history

Signs of failure to thrive, feeding problems, increased sweating, tachypnea, reduced physical capacity, or pallor?

Signs of heart failure (e.g., associated with relevant shunt defects such as a large VSD or left heart obstruction)

Is cyanosis present?

Defects with right-to-left shunts or relevant reduction of lung perfusion or parallel circulation of the two systems; examples: pulmonary atresia, tetralogy of Fallot, tricuspid atresia, TGA

Are there frequent respiratory infections?

Sign of a defect with increased lung perfusion (ASD, VSD, PDA)

Does the patient have syncopes or presyncopes (esp. associated with exertion)?

Typical signs of left heart obstruction (e.g., aortic stenosis, hypertrophic obstructive cardiomyopathy) in older children or adolescents

Table 11.2 Typical auscultation findings and other indicative findings in neonates and young infants with the most frequent cyanotic heart defects


Heart murmur

Point of maximum intensity / radiation

Other indicative findings

d-TGA simplex

No indicative heart murmur, possibly 1/6–2/6 systolic bruit

Parasternal 2nd left intercostal space (ICS)

Normal heart size, narrow upper mediastinum in X-ray (egg on its side)

Critical pulmonary stenosis

2/6–3/6 systolic bruit

Parasternal 2nd left ICS, radiation to the back

Usually decreased pulmonary vascular markings

Pulmonary atresia with/without VSD

2/6–3/6 systolic bruit

Parasternal 2nd left ICS

Decreased pulmonary vascular markings

Tetralogy of Fallot

2/6–3/6 systolic bruit

Parasternal 2nd left ICS, radiation to the back

Decreased pulmonary vascular markings, cyanotic spells usually only after early infancy

Total anomalous pulmonary venous connection

1/6–2/6 systolic bruit or no indicative heart murmur

Parasternal 2nd left ICS

Pronounced signs of heart failure; without obstruction of the pulmonary veins there is only slight cyanosis with clearly increased pulmonary vascular markings and cardiomegaly; with obstruction of the pulmonary veins there is pulmonary congestion and cyanosis

Truncus arteriosus communis

2/6–3/6 systolic bruit, additional (soft) diastolic bruit with truncus valve insufficiency

Parasternal 3rd left ICS

Heart failure, usually only slight cyanosis due to pulmonary recirculation

The characteristic findings of the most common heart defects on auscultation and other indicative findings in older children are summarized in Table 11.2 and Table 11.3 .

Heart defects with no indicative auscultation finding

It should be noted that some congenital heart defects do not cause a murmur in the first few days of life when pulmonary resistance is still high. For example, a ventricular septal defect (VSD) does not cause a murmur until there is a pressure gradient between the two ventricles after pulmonary vascular resistance drops and a relevant shunt develops.

Other examples of severe congenital heart defects that do not necessarily have an indicative auscultation finding are an isolated d-TGA (dextro-transposition of the great arteries) with no other accompanying heart defects or a hypoplastic left heart syndrome. A typical heart murmur may also be absent in the presence of severe heart failure. In these cases, cardiac output is no longer sufficient to generate a heart murmur.

Generally, only a systolic bruit is associated with patent ductus arteriosus (PDA) in neonates. The typical, continuous, machine-like systolic-diastolic heart murmur (to-and-fro murmur) does not develop until after pulmonary vascular pressure drops, when both systolic and diastolic pressures in the aorta are greater than the pressure in the pulmonary artery.


Organic heart murmurs are more common in neonates and young infants, while functional and innocent heart murmurs are more frequently found in older children. However, even severe heart defects can be present in neonates without an indicative heart murmur.

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Jun 13, 2020 | Posted by in CARDIOLOGY | Comments Off on 11 Cardiac Murmurs
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