At some point in time, ninety percent of children will have an audible heart murmur. Normal murmurs include vibratory and pulmonary flow murmurs, venous hums, carotid bruits, and the murmur of physiologic branch pulmonary artery stenosis.
1. Clinical evaluation of heart murmurs
Cyanosis, exercise intolerance, feeding difficulties, dyspnea, or syncope signify potential cardiac dysfunction. Failure to thrive, diffuse diaphoresis, unexplained persistent irritability or lethargy, and a typical chest pain also suggest the possibility of organic heart disease.
The majority of children who have heart murmurs are asymptomatic. In early infancy, however, cardiac malformations may manifest as persistent peaceful tachypnea (a respiratory rate greater than 60 breaths/min).
Family history of a congenital cardiovascular malformation increases the risk of a cardiac defect, such as with DiGeorge syndrome (type B interrupted aortic arch, truncus arteriosus).
2. Physical examination
: Twenty-five percent of children who have heart disease have extra cardiac anomalies. Diaphragmatic hernia,tracheoesophageal fistula and esophageal atresia, omphalocele, or imperforate anus are associated with congenital cardiac defects in infants.
Cyanotic infants or children, abnormal rate or pattern of breathing, a persistently hyperdynamic precordium, precordial bulging, or asymmetric pulses should be referred to a cardiologist.
Signs of congestive heart failure (inappropriate tachycardia, tachypnea, hepatomegaly, abnormal pulse volume) also should prompt referral to a cardiologist.
Auscultatorycriteria signifying cardiac disease
Loud, pansystolic, late systolic, diastolic, or continuous murmurs;an abnormally loud or single second heart sound.
Ejection or midsystolic clicks.
Ventricular septal defect (VSD) is a harsh pansystolic murmur of even amplitude that is audible at the lower left sternal border.
Patent ductus arteriosus (PDA) causes a murmur that is continuous, louder in systole, and located at the upper left sternal border.
Ejection (crescendo-decrescendo) murmurs are caused by ventricular outflow obstruction. Ejection murmurs begin after the first heart sound.
3. Differentiation of normal from pathologic murmurs
Criteria for diagnosis of a normal heart murmur
4. Heart murmurs in the newborn infant
- Asymptomatic patient.
- No evidence of associated cardiac abnormalities, extracardiac congenital malformations,orsyndromes.
- Auscultatory features are characteristic of an innocent murmur.
Sixty percent of healthy term newborn infants have normal heart murmurs. One-third of neonates who have serious heart malformations may not have a detectable heart murmur during the first 2 weeks of life. Thirty percent of newborn infants subsequently determined to have heart disease are discharged from the newborn nursery as ostensibly healthy.
Persistent peaceful tachypnea should not be dismissed; 90% of infants who have serious cardiac disease have persistent tachypnea after birth.
A persistently hyperdynamic precordium suggests organic heart disease.
Auscultation of the second heart sound.
In healthy neonates, the second heart sound is split audibly by 12 hours of age. A single second heart sound in a quiet neonate indicates:
- the absence of one outflow tract valve (aortic or pulmonary atresia);
- an abnormal position of the great vessels (transposition of the great arteries or tetralogy of Fallot);
- pulmonary hypertension (ventricular defect, persistent pulmonary hypertension).