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Approach to the infant or child with a cardiac murmur

Approach to the infant or child with a cardiac murmur
Literature review current through: Jan 2024.
This topic last updated: Jan 27, 2023.

INTRODUCTION — Heart murmurs are common in infants and children. Evaluation of a murmur is the most common reason for referral to a pediatric cardiologist [1,2]. While the prevalence of congenital heart disease is approximately 1 percent, a majority of children have innocent murmurs at some time [3,4]. Being able to distinguish a murmur associated with heart disease from a benign etiology is important for diagnosis and management (table 1). (See 'Distinguishing pathologic from innocent murmurs' below.)

The approach to the infant or child with a cardiac murmur will be reviewed here. Common causes of heart murmurs in childhood, the approach to identifying newborns with critical heart disease, and the approach to evaluating children with suspected heart disease are discussed separately:

(See "Common causes of cardiac murmurs in infants and children".)

(See "Identifying newborns with critical congenital heart disease".)

(See "Suspected heart disease in infants and children: Criteria for referral".)

Individual congenital heart defects are also discussed separately.

HISTORY — Several aspects of the history are useful in assessing the basis of a murmur (table 1):

Prenatal testing – Fetal echocardiography is performed during many pregnancies and can detect various forms of cyanotic or acyanotic congenital heart disease. (See "Congenital heart disease: Prenatal screening, diagnosis, and management".)

Pregnancy history – Certain maternal medical conditions can be associated with the development of congenital cardiac disease in the fetus (table 2).

Family history – The risk for congenital heart disease is higher if a first-degree relative (parent or sibling) has a structural congenital heart defect (table 2).

Other congenital anomalies – Various genetic syndromes are associated with an increased incidence of congenital heart disease (table 3).

Patient age – In the neonatal period, murmurs present in the first six hours of life are usually associated with a valve problem, either regurgitation (tricuspid valve or mitral valve) or stenosis (aortic valve or pulmonary valve). Murmurs detected after six hours of age are more likely to represent shunt lesions (eg, atrial or ventricular septal defects, patent ductus arteriosus) or peripheral pulmonary stenosis as these murmurs become more apparent as pulmonary vascular resistance falls. However, a valve problem may also present after six hours of age, particularly if an earlier examination was not performed or the neonate was uncooperative at the time of the initial examination. The presence of an early murmur does not rule out a septal defect. For example, neonates with tetralogy of Fallot (figure 1) typically have an early murmur of pulmonary stenosis but also have a ventricular septal defect [5]. (See "Common causes of cardiac murmurs in infants and children", section on 'Neonates and infants'.)

Murmurs detected in children beyond the age of one year often represent innocent murmurs but can also be produced by semilunar valve stenosis, atrioventricular valve regurgitation, or atrial septal defects. Other congenital heart lesions are unlikely to present at this age unless access to medical care was limited at an earlier age. A new murmur that occurs in a patient with a history of recent or frequent streptococcal pharyngitis may represent cardiac involvement with rheumatic fever. The left-sided valves are mainly involved in this condition, with mitral regurgitation more common than aortic regurgitation in acute cases. (See "Common causes of cardiac murmurs in infants and children", section on 'Children >1 year'.)

Symptoms – When evaluating an infant or child with a cardiac murmur, it is important to assess whether there are any symptoms concerning for heart disease (table 1). Concerning symptoms at any age include respiratory difficulties, diaphoresis (especially with exertion), and poor growth. In infants, symptoms may include poor feeding or excessive irritability. In older children, chest pain and syncope are important symptoms. Symptoms that may raise suspicion for heart disease in children are discussed in greater detail separately. (See "Suspected heart disease in infants and children: Criteria for referral", section on 'Symptoms'.)

CARDIOVASCULAR EXAMINATION — The physical examination should include careful review of the vital signs (including measurement of blood pressure in upper and lower extremities), assessment of heart rate and rhythm, assessment of pulses, and a detailed cardiovascular examination (including inspection, palpation, and auscultation of the chest) (table 1). Noncardiac physical examination findings that are suggestive of cardiac disease are discussed separately. (See "Suspected heart disease in infants and children: Criteria for referral", section on 'Physical examination findings' and "Identifying newborns with critical congenital heart disease", section on 'Physical examination'.)

Heart rate and rhythm — Normal heart rate varies with age (table 4). Abnormal heart rates (bradycardia or tachycardia) can be due to cardiac and noncardiac causes (table 5A-B). The approach to children with bradycardia or tachycardia is reviewed in detail separately. (See "Bradycardia in children" and "Approach to the child with tachycardia".)

An irregular rhythm should be assessed with an electrocardiogram. Sinus arrhythmia (characterized by phasic variation in heart rate with inspiration and expiration (waveform 1)) is a normal finding in children and does not warrant further evaluation. The evaluation of irregular heart rate in children is discussed separately. (See "Irregular heart rhythm (arrhythmias) in children".)

Pulses — Weak femoral pulses suggest coarctation of the aorta (figure 2). A differential pulse can also occur in patients with supravalvar aortic stenosis (AS), a condition that can direct more flow to the innominate artery (Coanda effect) [6]. Pulses may be diminished in the left arm in patients with an aberrant left subclavian artery, which may be a component of a vascular ring. (See "Clinical manifestations and diagnosis of coarctation of the aorta" and "Vascular rings and slings" and "Valvar aortic stenosis in children".)

Diffusely decreased pulses are associated with lowered cardiac output that can be present with myocardial dysfunction, cardiac tamponade, obstructive lesions, constrictive pericarditis, or Takayasu aortitis (pulseless disease). (See "Heart failure in children: Etiology, clinical manifestations, and diagnosis", section on 'Physical examination' and "Clinical manifestations and diagnosis of myocarditis in children", section on 'Physical examination' and "Clinical features and diagnosis of Takayasu arteritis" and "Cardiac tamponade".)

Bounding pulses occur when there is a large pulse pressure (ie, a large difference between systolic and diastolic pressure) and are classically associated with moderate to severe aortic regurgitation. In addition, bounding pulses may be seen with aortic runoff lesions, including patent ductus arteriosus (PDA) (figure 3), truncus arteriosus (figure 4), and aortopulmonary window. (See "Aortic regurgitation in children" and "Clinical manifestations and diagnosis of patent ductus arteriosus (PDA) in term infants, children, and adults".)

Inspection of the chest — The chest examination begins with careful observation and inspection. A visible apical impulse can be present in left ventricular volume overload lesions that include significant mitral or aortic valve regurgitation or large left-to-right shunts at the ventricular or great vessel level. A visible parasternal impulse can be present in right ventricular volume overload lesions, including significant pulmonary or tricuspid valve regurgitation, large atrial septal defect (ASD), and large arteriovenous malformation (AVM) [7].

Palpation of the chest — The following findings should be noted:

Apical impulse – The apical impulse is palpated using the tips of the middle and index fingers and is usually located in the fourth or fifth intercostal space in the left midclavicular line. The impulse is laterally displaced in lesions associated with a dilated left ventricle (aortic or mitral valve regurgitation, large left-to-right shunts at the ventricular or great vessel level). The impulse is more medial in patients with mesocardia or dextroposition (left-sided congenital diaphragmatic hernia, scimitar syndrome, left lobar emphysema) and is present in the right chest in patients with dextrocardia.

Right ventricular impulse – The right ventricular impulse is palpated by placing the hand along the left sternal border. The impulse is prominent in patients with right ventricular hypertension (eg, large ventricular septal defect [VSD], large PDA) or right ventricular volume overload (ASD, partial or total anomalous pulmonary venous connection (figure 5), large AVM).

Systolic thrill – A systolic thrill represents the tactile component of a loud murmur (grade 4 or higher) (table 6). Thrills are produced by flow across a stenotic site (subvalvar, valvar, supravalvar, or interventricular septum). A thrill associated with aortic or pulmonary stenosis is suggestive of severe obstruction; however, a thrill associated with a VSD does not necessarily indicate a large defect as it may be due to a large amount of left-to-right flow across the defect or a large pressure gradient between ventricles. The location and timing of a thrill aid in diagnosis and include:

Left lower sternal border – A systolic thrill at the left lower sternal border can occur with VSDs, as described above. Occasionally, patients with tricuspid regurgitation may have this finding if there is right ventricular hypertension.

Left upper sternal border – Severe pulmonary stenosis may produce a systolic thrill at the left upper sternal border.

Right upper sternal border – Severe AS may produce a systolic thrill at the right upper sternal border as long as cardiac output is normal.

Suprasternal notch – A systolic thrill in the suprasternal notch or over the course of the carotid artery can occur in patients with AS and, when present, is useful in distinguishing this condition from pulmonary stenosis.

Apex – A systolic thrill at the apex can occur in patients with mitral regurgitation.

Diastolic thrills – Diastolic thrills are uncommon but can occur in patients with severe mitral stenosis, aortic regurgitation, or pulmonary regurgitation and are located at the apex, right upper sternal border, or left sternal border, respectively.

Palpable second heart sound (S2) – A palpable S2 at the left upper sternal border indicates that a semilunar valve is closing under high pressure. This finding usually indicates the presence of severe pulmonary artery hypertension. The pulmonary valve typically is the most anterior of the four cardiac valves, and its closure can be palpated if pulmonary pressure is at or near systemic level. In patients with unrepaired transposition of the great arteries, the aortic valve is the most anterior valve and its closure can occasionally be palpated; such patients are also cyanotic.

AUSCULTATION OF HEART SOUNDS AND MURMURS — For thorough auscultation, it is helpful to focus on one aspect of the examination at a time: first heart sound (S1), second heart sound (S2), third heart sound (S3), fourth heart sound (S4), opening snap, ejection click, pericardial friction rub, and murmurs (systolic, diastolic, continuous) [5]. Murmurs are characterized last because details of the other components are required for accurate assessment.

Heart sounds — The first (S1) and second (S2) heart sounds are produced by closure of the atrioventricular (AV) and semilunar valves, respectively. Third (S3) and fourth (S4) heart sounds are usually associated with cardiac pathology.

First heart sound — S1 is produced by closure of the AV valves and corresponds to the QRS complex on the electrocardiogram (ECG). S1 is usually a single sound but, occasionally, is split if the mitral and tricuspid valves close at slightly different times. A split S1 can be a normal variation and also can occur in patients with right bundle branch block due to delayed closure of the tricuspid valve.

A split S1, if present, is usually more prominent at the left lower sternal border (tricuspid valve area) than the apex (mitral valve area). A perceived "split S1" that is more prominent at the apex may instead represent an early systolic ejection click produced by a bicuspid aortic valve (movie 1).

The intensity of S1 is increased when the valves close at greater velocity (eg, high-output states) or when there is greater excursion of valve leaflets (eg, short PR interval, mild mitral stenosis) since the elevated atrial pressure maintains a more open valve position. The intensity of S1 is decreased in low output states, mitral regurgitation due to failure of valve coaptation, and decreased valve excursion (long PR interval, severe mitral stenosis, elevated ventricular end-diastolic pressure) [8].

Second heart sound — S2 is produced by closure of the semilunar valves and is best heard at the left upper sternal border. The characteristics of S2 can provide important information about cardiac physiology:

Splitting – The aortic and pulmonary valve components of S2 normally vary with the respiratory cycle, being split in inspiration and single in expiration (movie 2). Physiologic splitting of S2 occurs due to decreased intrathoracic pressure during inspiration resulting in increased venous return to the right side of the heart, which in turn prolongs right ventricular systole and delays closure of the pulmonary valve (P2) [8]. Effects of inspiration on the left side of the heart are the opposite; pulmonary venous return decreases, left ventricular systole is shortened, and aortic valve closure (A2) occurs earlier. The normal split of S2 in inspiration is approximately 0.05 seconds. During expiration, intrathoracic pressure returns to baseline and the semilunar valves closure is perceived as a single sound. In children >3 years of age, the examiner can detect the physiologic split of S2 by focusing attention on expiration. In infants and younger children whose respiratory rate and heart rate are faster, usually the best an examiner can do is to note variability in S2 with some beats being single and others split without specifically correlating the findings with the respiratory cycle.

Wide splitting – In conditions that delay closure of the pulmonary valve, S2 is widely split but still varies during the respiratory cycle. These conditions include pulmonary valve stenosis, idiopathic dilation of the main pulmonary artery, and delayed electrical activation of the right ventricle as occurs with right bundle branch block (movie 3) [9]. Patients with severe mitral regurgitation can also have this feature due to earlier closure of the aortic valve associated with shortened left ventricular systole [10]. (See "Pulmonic stenosis in infants and children: Clinical manifestations and diagnosis" and "Right bundle branch block".)

Fixed splitting – S2 is widely split and fixed throughout the respiratory cycle in conditions associated with right ventricular volume overload, the most common of which is atrial septal defect (ASD) (movie 4). Other less common conditions include coronary sinus septal defect, large AVMs, and partial or total anomalous pulmonary venous connection (figure 5). The split of S2 can be as long as 0.10 second [8]. (See "Isolated atrial septal defects (ASDs) in children: Classification, clinical features, and diagnosis" and "Partial anomalous pulmonary venous return" and "Total anomalous pulmonary venous connection".)

Paradoxical splitting – This feature is uncommon in the first decade of life and is associated with delayed closure of the aortic valve that occurs with left bundle branch block. In such patients, in expiration, the aortic valve closes after the pulmonary valve; in inspiration, the effects on systemic and pulmonary venous return outlined with normal patients produce a single S2. Occasionally, patients with severe aortic stenosis (AS) can also have this feature. (See "Left bundle branch block" and "Valvar aortic stenosis in children".)

Intensity – The intensity of S2 depends on the pressure that closes the valve. After the neonatal transition period, the systolic pulmonary pressure is approximately one-fifth that of the systemic circulation. As a result, the pressure that closes the pulmonary valve is low and the pulmonary component of S2 is normally soft.

Reduced intensity – In patients with semilunar valve stenosis (aortic or pulmonary), the excursion of the affected valve is reduced and its closure sound is softened.

Increased intensity – In patients with pulmonary artery hypertension, the pulmonary valve closes both under high pressure and earlier since the elevated diastolic pressure in the pulmonary artery exceeds ventricular diastolic pressure sooner. This produces a loud pulmonic component to S2 (movie 5). The pulmonary valve is typically the most anterior of the four valves and is located in the immediate retrosternal region at the left upper sternal border. If the pulmonary component of S2 occurs close enough to the aortic component, S2 will be perceived as a single loud sound.

Patients with systemic arterial hypertension have an increased intensity of the aortic component of S2; since the aortic valve is positioned more posteriorly, this feature is not as apparent as the prominent pulmonary component in patients with pulmonary hypertension. Some forms of congenital heart disease are associated with an anteriorly positioned aorta (transposition or malposition of the great arteries) or a single semilunar valve (aortic atresia, pulmonary atresia); in such patients, S2 will be single and usually prominent.

Third and fourth heart sounds — S3 occurs in early diastole during the rapid filling phase and is best heard with the bell of the stethoscope. It occasionally can be heard in normal children if they are in a hyperdynamic state (movie 6), but it more often occurs in volume overload lesions such as a large VSD. This sound produces a cadence of "Ken-tuc-ky," with "Ken" representing S1, "tuc" representing S2, and "ky" representing S3. S3 can be generated by flow entering either ventricle and is heard best at the site of the corresponding AV valve (apex for the left ventricle and left lower sternal border for the right ventricle).

S4 is always a pathologic finding. S4 occurs in late diastole during the atrial contraction phase and is coincident with the P wave on the ECG. It is best heard with the bell of the stethoscope. S4 is produced by turbulence as blood enters a stiff ventricle and occurs with myocardial dysfunction or ventricular hypertrophy (eg, systemic hypertension (movie 7), semilunar valve stenosis, hypertrophic cardiomyopathy, and tachycardia-induced cardiomyopathy (movie 8)). The sound produces a cadence of "Ten-nes-see," with "Ten" representing S4, "nes" representing S1, and "see" representing S2.

If both S3 and S4 are present, a quadruple rhythm occurs. In such circumstances, with tachycardia and a corresponding shortened diastolic period, S3 and S4 occur close enough together that they are detected as a single extra sound and a summation gallop is present.

Other sounds — The presence of an opening snap, clicks, and/or rubs may provide additional information:

Opening snap – An opening snap occurs with mitral stenosis and is best heard at the apex immediately preceding the murmur (movie 9). As mitral stenosis progresses and leaflet mobility decreases, this sound becomes softer and occurs earlier in diastole.

Ejection click – Ejection clicks are sharp, brief, high-frequency sounds that have a different quality from S1 and S2. They are usually produced by abnormal valves. By noting the timing and location on the precordium, the source of the click can be determined (table 7). The mid or late systolic apical click associated with mitral valve prolapse may be associated with a murmur of mitral regurgitation that is more easily heard when the patient is standing rather than sitting or supine because of increased prolapse that occurs with reduced left ventricular volume in a more upright posture (movie 10 and movie 11). The early systolic click associated with a bicuspid aortic valve is best heard at the apex (movie 1) rather than the typical position for auscultation of the aortic valve (ie, right upper sternal border). It may be difficult to distinguish this finding from a split S1. The early systolic click associated with valvar pulmonary stenosis is best heard at the left upper sternal border and is variable, becoming softer in inspiration due to decreased excursion of the stenotic valve leaflets (movie 12) [10]. Ebstein anomaly of the tricuspid valve can produce a mid or late systolic click at the left lower sternal border. (See "Pulmonic stenosis in infants and children: Clinical manifestations and diagnosis" and "Ebstein anomaly: Clinical manifestations and diagnosis".)

Ejection clicks can occasionally be present with nonvalve diagnoses including dilation of the ascending aorta or pulmonary artery (heard at the upper sternal border), and membranous VSD (figure 6) associated with aneurysm of the ventricular septum (heard at the left lower sternal border). Patients with patent ductus arteriosus (PDA) can have multiple ejection clicks at the left upper sternal border created by wave-like expansion of the main pulmonary artery associated with the left-to-right shunt (movie 13). (See "Clinical manifestations and diagnosis of patent ductus arteriosus (PDA) in term infants, children, and adults" and "Isolated ventricular septal defects (VSDs) in infants and children: Anatomy, clinical features, and diagnosis", section on 'Introduction'.)

Pericardial friction rub – A pericardial friction rub occurs with pericarditis and is a grating sound similar to rubbing two pieces of sandpaper together. It is created when inflamed pericardial and visceral pericardial surfaces rub together and is therefore absent with a large pericardial effusion. It is louder when the patient sits up and leans forward, usually has inspiratory accentuation, can be present throughout all phases of the cardiac cycle, and is loudest along the left sternal border (movie 14).

Heart murmurs — Characterizing the intensity, timing, location, radiation, shape, and quality of the heart murmur helps determine the anatomic basis.

Intensity — The intensity of a murmur is graded on a scale of 1 to 6 (table 6) [11]. A precordial thrill is present for murmurs grade ≥4. The intensity of a murmur depends on both the pressure gradient and flow across the site. A neonate with a large VSD will have a soft murmur on the second day after birth, but after several weeks as pulmonary vascular resistance falls and the left-to-right shunt increases, the murmur becomes louder and a systolic thrill may become detectable at the left lower sternal border. (See "Isolated ventricular septal defects (VSDs) in infants and children: Anatomy, clinical features, and diagnosis".)

Timing — Murmurs can occur in either or both of the phases of the cardiac cycle (table 8):

Systolic murmurs:

Early systolic (eg, small muscular VSD (movie 15))

Midsystolic or systolic ejection (eg, AS (movie 16))

Holosystolic or pansystolic (eg, membranous, malalignment, and moderate or large muscular VSDs (movie 17); mitral regurgitation (movie 18))

Diastolic murmurs:

Early diastolic (eg, aortic regurgitation (movie 19), ASD with right ventricular volume overload and "relative" tricuspid stenosis (movie 20))

Late diastolic or presystolic (eg, mitral stenosis (movie 9))

Continuous murmur (eg, PDA (movie 13), benign venous hum (movie 21))

To-and-fro murmurs, which represent two distinct murmurs (eg, combined AS and aortic regurgitation (movie 22), combined pulmonary stenosis, and pulmonary regurgitation (movie 23))

Location and radiation — The likely cause of a murmur can be determined by noting the region on the precordium where the murmur is maximally heard and the pattern of radiation.

Right upper sternal border — Systolic murmurs at the right upper sternal border are associated with left ventricular outflow obstruction (AS at the subvalvar, valvar (movie 16), or supravalvar level) and with "relative AS" associated with hyperdynamic states. Left ventricular outflow tract obstructive lesions typically have radiation of the murmur to the carotid region. (See "Valvar aortic stenosis in children" and "Subvalvar aortic stenosis (subaortic stenosis)".)

Left upper sternal border — Systolic murmurs at the left upper sternal border can represent right ventricular outflow tract obstruction (pulmonary stenosis at the subvalvar, valvar (movie 12), or supravalvar level), peripheral pulmonary stenosis, relative stenosis associated with right ventricular volume overload lesions (eg, ASD (movie 4)), or benign flow murmurs. The murmur of peripheral pulmonary stenosis radiates to the axilla and the back. The pulmonary valve is the most anteriorly positioned valve and normal flow across it can often be detected, especially in thin individuals. (See "Pulmonic stenosis in infants and children: Clinical manifestations and diagnosis" and "Isolated atrial septal defects (ASDs) in children: Classification, clinical features, and diagnosis".)

Diastolic murmurs at the left upper sternal border can represent aortic regurgitation (movie 19) or pulmonary regurgitation. The degree of regurgitation often correlates with the degree of radiation along the left sternal border.

A continuous murmur at the left upper sternal border occurs with PDA (movie 13) and does not vary with body position. A continuous murmur associated with coronary artery fistula is typically somewhat lower on the sternal border (movie 24). A continuous murmur at the left or right upper sternal border can also represent a cervical venous hum (movie 21); such murmurs are also present in the infra- or supraclavicular regions, are more prominent in diastole, become louder with extension of the neck when the patient is sitting, and become softer or resolve with flexion or rotation of the neck or if light pressure is placed over the cervical triangle when the patient is sitting or supine.

Left lower sternal border — Systolic murmurs at the left lower sternal border can represent VSDs (movie 15 and movie 17), tricuspid regurgitation, subvalvar AS, hypertrophic cardiomyopathy (HCM), or an innocent murmur initially described in 1915 by a London clinician, Dr. George Still [12].

An innocent murmur has a characteristic vibratory or musical quality and is typically louder when the patient is supine or if there is a hyperdynamic state associated with fever or anxiety (movie 25). Patients with tricuspid regurgitation have inspiratory increase in the intensity of the murmur. Subvalvar AS and HCM produce systolic ejection murmurs that can be distinguished with the Valsalva maneuver (in patients who are able to cooperate), during which the intensity of the murmur typically decreases in fixed subvalvar AS and increases in HCM.

Diastolic murmurs at the left lower sternal border can represent radiation of semilunar valve regurgitation (movie 19), or tricuspid stenosis that is either real or relative (movie 20), as noted in the timing section above.

Apex — Systolic murmurs at the apex represent mitral regurgitation (movie 18). This type of murmur usually radiates to the axilla. Diastolic murmurs at the apex represent mitral stenosis that is either real (movie 9) or relative. Such murmurs are easier to detect when the patient is in the left lateral decubitus position.

Other locations — Some murmurs are not present on the precordium but are located in other regions. Coarctation of the aorta (figure 2) can produce a systolic murmur on the back between the scapulae, near the region of obstruction at the aortic isthmus. If the coarctation is longstanding and severe, collateral arteries develop and produce a continuous murmur in the lateral region of the chest. Large AVMs produce continuous murmurs in the affected region; relatively common sites include the cranium in patients with vein of Galen malformation, and the right upper quadrant in patients with a hepatic lesion.

Shape — Systolic murmurs associated with obstructive lesions create a diamond-shaped murmur (also called crescendo-decrescendo), with more severe obstruction causing peak murmur intensity later in systole (movie 16). Diamond-shaped murmurs also occur with increased flow across normal semilunar valves in hyperdynamic states associated with fever, anemia, anxiety, or hyperthyroidism, or with right ventricular volume overload in patients with ASD.

Holosystolic murmurs have a plateau shape, continuing from S1 to S2. Holosystolic murmurs may be caused by AV valve regurgitation (movie 18) or membranous (movie 17), malalignment, and moderate/large muscular VSDs.

Semilunar valve regurgitation typically has a decrescendo quality, becoming softer further into diastole (movie 19).

Quality — Certain adjectives are traditionally used to categorize murmurs. While such characterization is somewhat subjective, the following examples illustrate these terms:

Harsh – A harsh murmur is characteristic of an obstructive lesion such as AS (movie 16) or pulmonary stenosis (movie 12).

Blowing – A blowing murmur is typical of a systolic murmur of AV valve regurgitation (movie 18) or the diastolic murmur of semilunar valve regurgitation (movie 19).

Rumbling – A rumbling murmur describes the low frequency diastolic murmur of mitral stenosis (movie 9).

Vibratory or musical – A vibratory or musical murmur is characteristic of the innocent murmur of childhood that is typically present at the left lower sternal border. This quality has been likened to having a jar of bumblebees with their wings fluttering or a loose guitar string that is reverberating (movie 25).

SYNTHESIZING THE FINDINGS — In order to assess the likelihood of cardiac disease in a child with a heart murmur, the components of the physical examination must be considered together. The location and timing of the murmur may suggest certain diagnostic possibilities, and additional findings (eg, second heart sound [S2] splitting, clicks, radiation, gallop rhythm) provide further clues as to the etiology of the murmur and the severity of the lesion. A stepwise approach is helpful. Examples of commonly encountered scenarios include:

A child with a systolic ejection murmur (SEM) at the left upper sternal border (algorithm 1)

A child with a SEM at the right upper sternal border (algorithm 2)

A child with a holosystolic murmur at the left lower sternal border (algorithm 3)

DISTINGUISHING PATHOLOGIC FROM INNOCENT MURMURS — Certain features can help distinguish pathologic from innocent murmurs (table 1):

Pathologic murmurs – Features associated with cardiac disease include the following [13-15]:

Grade ≥3 intensity (table 6) – Lesions associated with increased turbulence are associated with a louder murmur.

Holosystolic timing – This occurs with ventricular septal defects other than small muscular defects (movie 17), and in some patients with atrioventricular valve regurgitation (movie 18) or ventricular outflow obstruction.

Maximum intensity at the left upper sternal border – A murmur in this location can occur with atrial septal defects (ASDs) (movie 4) or pulmonary stenosis (movie 12), although innocent murmurs (movie 21) also commonly occur at this site. Other features of the examination (eg, the quality of the second heart sound [S2] and systolic clicks) help distinguish the basis of the murmur (algorithm 1).

Harsh or blowing quality – These qualities are seen with obstructive lesions (movie 16 and movie 12) or regurgitant valves (movie 18 and movie 19), respectively.

Abnormal S2 – A wide and fixed split S2 occurs with right ventricular volume overload lesions, most commonly ASDs (movie 4). A single prominent S2 mainly occurs with pulmonary hypertension (movie 5) but also can occur in conditions associated with a single semilunar valve or anteriorly positioned aorta.

Systolic click (movie 1 and movie 12) – A click usually indicates an abnormal valve with the timing (early or midsystolic), precordial location, and characteristics (constant or variable) having features distinct for each valve (table 7).

Diastolic murmur – Murmurs in diastole (movie 19 and movie 20 and movie 9) are rarely innocent and should be considered abnormal [4]. A venous hum (movie 21) is a normal finding and may have diastolic accentuation; this murmur is continuous rather than isolated to diastole, however [16].

Increased intensity with upright position – Most innocent murmurs (with the exception of cervical venous hum (movie 21)) typically become softer in the upright position.

Gallop rhythm (third heart sound [S3] or fourth heart sound [S4]) (movie 6 and movie 7 and movie 8) – While an S3 gallop is occasionally heard in normal children, the presence of either S3 or S4 should prompt evaluation of ventricular size and function.

A friction rub (movie 14) – A pericardial friction rub occurs with pericarditis. Viral infection and postpericardiotomy syndrome are the most common etiologies of pericarditis in children, though there are many other etiologies. (See "Acute pericarditis: Clinical presentation and diagnosis" and "Post-cardiac injury syndromes".)

Innocent murmurs – Features associated with innocent murmurs include the following [13-15]:

Grade ≤2 intensity – Flow murmurs and innocent Still murmur (movie 25) are usually grade 1 or 2 in intensity

Softer intensity when the patient is sitting compared with when the patient is supine

Short systolic duration (not holosystolic, not diastolic)

Minimal radiation – The murmur is located in a limited region of the precordium

Musical or vibratory quality

While heart murmurs are common in pediatric patients, only a minority of patients have a structural heart defect. The association of murmurs with heart disease is higher in infants and decreases with age during childhood and adolescence [13,14]. In a study of 222 pediatric patients (age range 2 days to 18 years, median age 1.9 years) referred for evaluation of a murmur to a pediatric cardiologist, approximately one-third had cardiac disease [15]. Such a study group represents a preselected sample; the percent of patients with murmurs associated with heart disease in a general pediatric practice is likely much lower.

CRITERIA FOR REFERRAL — Patients should be referred to a pediatric cardiologist if there are any of the above listed features associated with cardiac disease (table 1). (See 'Distinguishing pathologic from innocent murmurs' above.)

In addition, referral is warranted if any of the following findings or conditions are present:

Weak femoral pulses and/or >10 mmHg systolic blood pressure gradient between the right arm and leg (suggestive of coarctation of the aorta (figure 2))

Generalized decreased pulses (suggesting myocardial dysfunction)

Wide pulse pressure (suggestive of aortic regurgitation or patent ductus arteriosus (figure 3))

Abnormal fetal echocardiogram

Syndrome associated with increased likelihood of congenital heart disease (table 3)

If the primary care provider has any questions regarding whether referral is appropriate or the timing of referral, they should discuss the patient with a pediatric cardiologist by phone. In many cases, a follow-up assessment can be useful before referral to a cardiologist.

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or email these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient education" and the keyword[s] of interest.)

Basics topic (See "Patient education: Heart murmurs (The Basics)".)

SUMMARY AND RECOMMENDATIONS

Introduction – Heart murmurs are common in infants and children, but only a minority of patients with murmurs have heart disease. The association of murmurs with heart disease is higher in infants and decreases with age during childhood and adolescence. Being able to distinguish a murmur associated with heart disease from a benign etiology is important for diagnosis and management. (See 'Introduction' above and 'Distinguishing pathologic from innocent murmurs' above.)

History – In reviewing the history of an infant or child with a heart murmur, it is helpful to consider the prenatal history (including maternal conditions and whether fetal echocardiography was performed during the pregnancy) (table 2), the family history (particularly, history of congenital heart disease), whether the child has a genetic syndrome or other congenital anomaly (table 3), the patient's age, and whether there are any concerning symptoms (table 1). (See 'History' above.)

Physical examination – The physical examination should include careful review of the vital signs and a detailed cardiovascular examination, including assessment of heart rate and rhythm; assessment of pulses; and inspection, palpation, and auscultation of the chest. (See 'Cardiovascular examination' above.)

Auscultation of heart sounds – For thorough auscultation, it is helpful to focus on one aspect of the examination at a time (see 'Auscultation of heart sounds and murmurs' above):

First and second heart sound (S1 and S2), including assessment of S2 splitting and intensity (movie 2 and movie 4 and movie 5 and movie 3)

Assessment for third or fourth heart sounds (S3 and S4) (movie 6 and movie 7 and movie 8)

Assessment for other heart sounds, including opening snap (movie 9), clicks (movie 1 and movie 12 and movie 13 and movie 10 and table 7), and friction rub (movie 14)

Characterization of the murmur, including intensity (table 6), timing (table 8), location, radiation, shape, and quality

Synthesizing the findings – In order to assess the likelihood of cardiac disease in a child with a heart murmur, the components of the physical examination must be considered together. The location and timing of the murmur may suggest certain diagnostic possibilities, and additional findings (eg, S2 splitting, clicks, radiation, gallop rhythm) provide further clues as to the etiology of the murmur and the severity of the lesion. A stepwise approach is helpful, as shown in the figures outlining the approach for a systolic ejection murmur (SEM) at the left upper sternal border (algorithm 1), SEM at the right upper sternal border (algorithm 2), and holosystolic murmur at the left lower sternal border (algorithm 3). (See 'Synthesizing the findings' above.)

Features of pathologic murmurs – Features associated with cardiac disease include (table 1) (see 'Distinguishing pathologic from innocent murmurs' above):

≥Grade 3 intensity (table 6)

Holosystolic timing (movie 17 and movie 18)

Maximum intensity at the left upper sternal border (algorithm 1 and movie 4 and movie 12 and movie 21)

Harsh (movie 16 and movie 12) or blowing (movie 18 and movie 19) quality

Abnormal S2 (movie 4 and movie 5)

Systolic click (movie 1 and movie 12 and table 7)

Diastolic murmur (movie 9 and movie 19 and movie 20)

Increased intensity with upright position

Gallop rhythm (S3 or S4) (movie 6 and movie 7 and movie 8)

Friction rub (movie 14)

Referral – Patients should be referred to a pediatric cardiologist if any of the following findings or conditions are present (see 'Criteria for referral' above):

Murmur is associated with any of the above listed pathologic features (table 1)

Weak femoral pulses and/or >10 mmHg systolic blood pressure gradient between the right arm and leg (suggestive of coarctation of the aorta (figure 2))

Generalized decreased pulses (suggesting myocardial dysfunction)

Wide pulse pressure (suggestive of aortic regurgitation or patent ductus arteriosus (figure 3))

Abnormal fetal echocardiogram

Syndrome associated with increased likelihood of congenital heart disease (table 3)

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