Abnormal Heart Sounds

Abnormal Heart Sounds: Excerpt from In A Page: Pediatric Signs and Symptoms

Abnormal heart sounds are common in pediatric patients and usually benign. Approximately 50% of children will have an innocent murmur at some time, compared to a 1% incidence of congenital heart disease (nearly all of which present by 1 year of age).

Differential Diagnosis

• Abnormal S2 –Most important auscultatory finding; normally, S2 is single on inspiration and narrowly split on expiration, indicating normal pulmonary arterial pressures; difficult to learn, especially in babies with fast heart rates or a screaming child
  –Single and/or loud S2: Increased pulmonary artery pressure (large L to R shunt, pulmonary hypertension), also seen in patients with only single outlet from heart (i.e., pulmonary atresia)
  –Wide fixed-split S2: ASD, right bundle branch block, post-cardiac surgery

• Systolic murmur
  –Up to 50% of children at some point in life
  –Mid-systolic/ejection type: S1 and S2 separate from the murmur (lub-shhh-dub), due to flow across semilunar valve, harsh indicates semilunar valve stenosis, whereas low-pitched, vibratory, musical indicates innocent murmur
  –Holosystolic/regurgitant murmur: Begins with S1 (which is not clearly heard); always pathologic (mitral valve regurgitation, VSD, subaortic stenosis)

• Diastolic sounds
  –Always abnormal
  –Early and medium/high pitch murmur indicates semilunar valve insufficiency, low frequency rumbling indicates mitral/tricuspid stenosis
  –S3/S4/opening snap: Soft S3 can be normal in healthy children; any sound clearly heard is probably an abnormality of the mitral/tricuspid valve (opening snap) or ventricular filling (S3/S4)

• Continuous murmur
  –Murmur in systole that continues into diastole (may not fill entire diastole)
  –Venous hum: Low pitched, continuous murmur at both upper sternal borders; disappears when supine; innocent
  –Patent ductus arteriosus: Harsh, machinery-like murmur at left upper sternal border (LUSB)

• Systolic ejection click
  –High-pitched sound
  –Early: Bicuspid aortic valve, loudest at apex/LLSB, often confused with split S1
  –Mid/late: Mitral valve prolapse

Workup and Diagnosis

• Majority of murmurs heard after the first year of life are systolic and innocent

• Major innocent murmurs of childhood: All must have a normal S2 and no symptoms
  –Still (vibratory) murmur: Vibratory, musical, twangy midsystolic murmur loudest at the LLSB, louder when supine, heard in toddlers
  –Venous hum: Continuous low rumbling sound at upper sternal borders, disappears when supine
  –Peripheral pulmonary stenosis (PPS): Midsystolic murmur at LUSB, radiates to back and both axillae, normal up to 1 year of age (refer for evaluation if present afterwards)
  –Innocent pulmonary flow murmur: Midsystolic murmur, LUSB, loudest when supine, adolescent age range

• Physical exam: Assess growth pattern, heart rate, organomegaly, and femoral pulses
• Four-limb blood pressures very helpful in evaluating possible aortic coarctation (higher BP in arms, lower in legs)
• Chest X-ray: Rarely useful in the routine evaluation of murmurs in children (unless pathology likely)
• 12-lead electrocardiogram useful for assessment of atrial or ventricular enlargement/hypertrophy
• Pulse-oximetry is very useful in the newborn to rule out mildly cyanotic lesions
• Echocardiography

Treatment

• Innocent murmurs
  –Parental reassurance that this is a normal, common finding in children representing normal blood flowing through a normal heart, usually disappearing with age (as the patient grows, the stethoscope is farther from the heart, so the sound isn’t heard)
  –The murmur may get louder during times of increased cardiac output (i.e., illness, fever, dehydration, activity, or other stress)
  –No bacterial endocarditis prophylaxis required

• Abnormal findings requiring referral
  –Abnormal S2 (single or widely split)
  –Holosystolic/regurgitant murmur
  –Any diastolic sounds
  –Systolic ejection clicks: “Harsh” murmurs
  –Any murmur with cardiac symptoms
• Further treatment is dependent on underlying anatomy and physiology

Book Source Details

• Book Title: In A Page: Pediatric Signs and Symptoms
• Author(s): Jonathan E. Teitelbaum, Kathleen O. Deantonis, Scott Kahan
• Year of Publication: 2007
• Copyright Details: In A Page: Pediatric Signs and Symptoms, Copyright © 2007 Lippincott Williams & Wilkins.

More About Heart Murmur

• Back to disease: Heart Murmur: Introduction
• Next Book Extract About Heart Murmur: Tachycardia/Palpitations (In A Page: Pediatric Signs and Symptoms)
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.

More About This Book: Title: In A Page: Pediatric Signs and Symptoms Authors: Jonathan E. Teitelbaum, Kathleen O. Deantonis, Scott Kahan Publisher: Lippincott Williams & Wilkins Copyright: 2007 ISBN: 1-4051-0427-9

 » Next page: Tachycardia/Palpitations (In A Page: Pediatric Signs and Symptoms)

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