11 Cardiac Murmurs



10.1055/b-0035-121506

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

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













































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

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.

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