Overview
This lecture reviews the clinical approach to evaluating pediatric heart murmurs, emphasizing distinguishing innocent from pathologic murmurs based on history, exam, and when further investigation or referral is needed.
Innocent vs Pathologic Heart Murmurs
- Most heart murmurs in children are innocent and do not indicate heart defects.
- Innocent murmurs are always asymptomatic, early ejection systolic, soft, short, at the sternal edge, and without added sounds.
- Symptomatic murmurs are always pathologic, but some pathologic murmurs can be asymptomatic.
- Diastolic (except venous hum) and pansystolic murmurs are always pathologic.
Clinical History
- Ask about symptoms of cardiac failure: poor feeding, breathlessness, sweating during feeding, and failure to thrive in infants.
- Older children: ask about exercise intolerance, exertional chest pain, and syncope.
- Note family history of sudden death or congenital heart disease.
- Review birth history, developmental history, and maternal illnesses or medication exposures.
- Ask when the murmur was first detected, as timing can suggest the type of lesion.
Physical Examination
- Observe for cyanosis, respiratory distress, and syndromic features (e.g., Down syndrome, Marfan syndrome).
- Assess for clubbing and peripheral perfusion.
- Check pulses for quality; weak or unequal pulses may indicate specific defects.
- Palpate for thrills and abnormal cardiac impulses.
- Auscultate for heart sounds, extra sounds (clicks, S3, S4), murmur timing, intensity, quality, location, and radiation.
Common Lesions and Their Features
- Down syndrome commonly associated with atrioventricular septal defects and ventricular septal defects.
- Coarctation of the aorta shows stronger upper extremity pulses.
- Patent ductus arteriosus presents as a continuous, machinery-like murmur.
- Transposition of great vessels causes cyanotic congenital heart disease.
Investigations and Management
- Initial investigations: chest X-ray, ECG, and four-limb blood pressure.
- Refer to cardiology for suspicious or pathologic murmurs; further tests may include echocardiography and cardiac catheterization.
- Management may be medical, surgical, or both, addressing the underlying defect and complications.
Key Terms & Definitions
- Innocent murmur — a benign heart murmur with no underlying structural heart disease.
- Pathologic murmur — heart murmur due to structural heart defects or disease.
- Cyanosis — bluish discoloration indicating low oxygen levels.
- Thrill — palpable vibration from turbulent blood flow.
- Atrioventricular septal defect — a congenital defect involving the atrial and ventricular septa and valves.
Action Items / Next Steps
- Practice focused history and physical examination for pediatric murmurs.
- Memorize features differentiating innocent from pathologic murmurs.
- Review underlying heart lesions commonly seen with genetic syndromes.
- Read about interpretation of pediatric ECG and chest X-ray findings.