Pediatric Murmur

Aka: Pediatric Murmur, Heart Murmur in Children, Innocent Murmur

1. See Also
   1. Congenital Heart Disease
   2. Heart Murmur
   3. Systolic Murmur
   4. Diastolic Murmur
2. Epidemiology
   1. 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
   2. 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
   3. 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
   4. References
      1. Kang (2015) Arch Dis Child 100(11): 1028-31 [PubMed]
      2. Yoon (2020) BMC Pediatr 20(1): 322 [PubMed]
3. Causes: Innocent Murmurs
   1. Still's Murmur (Aortic Vibratory Systolic)
      1. Most common Innocent Murmur
   2. Venous Hum of late infancy and early childhood
      1. Second most common Innocent Murmur
   3. Septal hypertrophy due to myocardial fat deposition
      1. Resolves over six months
   4. Pulmonary Flow Murmur
   5. Neonatal Pulmonary branch murmur
   6. Physiologic Peripheral Pulmonary Stenosis
   7. Supraclavicular Murmur (Brachiocephalic systolic murmur)
   8. Aortic systolic murmur
   9. Mammary artery souffle
4. Causes: Pathologic Murmurs
   1. Ventricular Septal Defect (VSD) 20-25%
   2. Atrial Septal Defect (ASD) 8-13%
   3. Patent Ductus Arteriosus (PDA) 6-11%
   4. Tetralogy of Fallot: 10%
   5. Pulmonary Stenosis: 9%
   6. Pulmonary Artery Stenosis: 7%
   7. Aortic Coarctation: 5-8%
   8. Aortic Stenosis: 5-6%
   9. Transposition of Great Vessels: 5%
   10. Mitral Valve Prolapse 4%
   11. Total anomalous pulmonary venous congestion (2-3%)
   12. Tricuspid Atresia: 1-2%
   13. Hypoplastic Left Heart: Rare
   14. Truncus Arteriosus: rare
5. HIstory
   1. See Congenital Heart Disease
   2. Past Medical History
      1. Acute Rheumatic Fever
      2. Multisystem Inflammatory Syndrome (or Kawasaki Disease)
      3. Genetic Syndrome
         1. See Congenital Heart Disease for associated conditions
         2. One major or 3 minor findings of Genetic Syndrome
      4. Teratogen Exposure in Pregnancy and other prenatal factors
         1. See Congenital Heart Disease
   3. Family History
      1. Congenital Heart Disease
         1. Relative Risk increased to 3 to 24 if sibling has Congenital Heart Disease
      2. Hypertrophic Cardiomyopathy
         1. Screening Echocardiogram in first degree relatives
      3. Sudden Cardiac Death (or unexplained death) in young relatives
6. Exam
   1. See Heart Murmur
   2. See Systolic Murmur
   3. See Diastolic Murmur
   4. See Congenital Heart Disease
7. Signs: Innocent Murmurs
   1. Precaution: These signs are unreliable in under age 1 year due to higher Incidence of Congenital Heart Disease
   2. 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)
   3. 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
8. Signs: Pathologic Murmur
   1. See Congenital Heart Disease
   2. Red flag general exam findings
      1. Evidence of Failure to Thrive
      2. Lethargy
      3. Cyanosis
      4. Shortness of Breath
      5. Parasternal heave or thrill
      6. Murmur radiates to back or neck (e.g. carotid arteries)
      7. Murmur increases in loudness on standing or with Valsalva Maneuver
   3. Auscultation (6 Cardinal signs of pathology)
      1. Harsh murmur
      2. Pansystolic murmur or Diastolic Murmur
      3. Loud Murmur Grade 3 or more
      4. Murmur at high Left sternal border
      5. Early or Midsystolic click or murmur
      6. Fixed Split S2, or S3 or S4 Heart Sounds
9. Diagnosis: Innocent Murmur (all 4 criteria required)
   1. No abnormal physical findings
   2. No symptoms suggestive of Congenital Heart Disease
   3. 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)
   4. Auscultation findings consistent with Innocent Murmur and no red flags suggesting pathologic murmur (see above)
10. Management: Approach
    1. 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
    2. 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.
11. Management: Pathologic murmur suspected
    1. Newborn to eight weeks
       1. See Congenital Heart Disease for evaluation
    2. Pediatric Cardiology Referral
       1. Do not create preconceived notions of evaluation
       2. Not every Pediatric Murmur will need Echocardiogram
12. Management: Innocent Murmur suspected
    1. Trust skilled clinical evaluation
    2. Study of clinical exam by pediatric cardiolgists
       1. Exam is as accurate as Echocardiogram
       2. Exam is more accurate than Electrocardiogram
       3. Test Sensitivity: 96%
       4. Test Specificity: 95%
       5. Positive Predictive Value: 88%
       6. Negative Predictive Value: 98%
    3. Reference
       1. McCrindle (1996) Arch Pediatr Adolesc Med [PubMed]
13. References
    1. Frank (2011) Am Fam Physician 84(7): 793-800 [PubMed]
    2. Ford (2022) Am Fam Physician 105(3): 250-61 [PubMed]