Pediatric Murmur

Overall Murmur Prevelance: 50% of all children (range 20 to 80%)
1. Innocent Murmurs more common than pathologic 10:1, especially over age 1 year
2. After infancy, only 1% of childhood murmurs are associated with structural heart disease
Heart Murmurs are found in up to 8% of asymptomatic newborns
1. Even without signs of Congenital Heart Disease, 37% will be diagnosed with Congenital Heart Disease
2. Of infants with murmur, 2.5% will have a Critical Congenital Heart Disease lesion requiring early intervention
Age of murmur onset related to pathology
1. Murmur onset at 24 hours of life: 8% pathologic
2. Murmur onset at 6 months of life: 14% pathologic
3. Murmur onset at 12 months of life: 2% pathologic
References
1. Kang (2015) Arch Dis Child 100(11): 1028-31 [PubMed]
2. Yoon (2020) BMC Pediatr 20(1): 322 [PubMed]

Still's Murmur (Aortic Vibratory Systolic)
1. Most common Innocent Murmur
Venous Hum of late infancy and early childhood
1. Second most common Innocent Murmur
Septal hypertrophy due to myocardial fat deposition
1. Resolves over six months
Pulmonary Flow Murmur
Neonatal Pulmonary branch murmur
Physiologic Peripheral Pulmonary Stenosis
Supraclavicular Murmur (Brachiocephalic Systolic Murmur)
Aortic Systolic Murmur
Mammary artery souffle

Precaution: These signs are unreliable in under age 1 year due to higher Incidence of Congenital Heart Disease
Auscultation (Seven S's - key reassuring findings in Innocent Murmurs)
1. Sensitive
  1. Murmur accentuates with position changes, activity - see below
2. Short duration
  1. Not holosystolic
3. Single
  1. Isolated murmur without click, gallup or other extra heart sounds
4. Small
  1. Murmur limited to small, focal distribution without radiation
5. Soft
  1. Low amplitude (e.g. II/VI murmur)
6. Sweet
  1. Non-harsh quality
7. Systolic
  1. Limited to systole (Diastolic Murmurs are typically pathologic)
Accentuation maneuvers (Innocent Murmurs become louder in this position)
1. Sitting forward
2. Exercise or increased Heart Rate
3. Fever
4. Anxiety, Restlessness, or crying

No abnormal physical findings
No symptoms suggestive of Congenital Heart Disease
No increased risk of Congenital Heart Disease by history
1. See Above
2. No first degree relative Family History of Congenital Heart Disease
3. No Genetic Syndrome suspected (1 major finding or 3 minor findings)
Auscultation findings consistent with Innocent Murmur and no red flags suggesting pathologic murmur (see above)

Murmurs in newborns and children under age 1 year
1. Newborns are higher risk for Congenital Heart Disease (esp. Genetic Syndrome, first degree relative with CHD)
2. Refer to pediatric cardiology (first week of life)
3. Echocardiogram
Murmurs in older children and teens
1. An Innocent Murmur that definately meets all above criteria does not require further evaluation or referral
  1. Systolic Murmur without cardiopulmonary or Congenital Heart Disease findings
  2. Repeat exam (physiologic murmurs typically resolve by repeat exam)
2. Other murmurs should be referred for evaluation by cardiology and/or Echocardiogram (depending on local protocols)
  1. Pediatric cardiology can often make diagnosis without Echocardiogram and may prevent unnecessary testing.

Newborn to eight weeks
1. See Congenital Heart Disease for evaluation
Pediatric Cardiology Referral
1. Do not create preconceived notions of evaluation
2. Not every Pediatric Murmur will need Echocardiogram