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.
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.
Question | Significance |
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 |
Diagnosis | 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.
Note
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.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
