II. Epidemiology
- Overall Murmur Prevelance: 50% of all children (range 20 to 80%)
- Innocent Murmurs more common than pathologic 10:1, especially over age 1 year
- After infancy, only 1% of childhood murmurs are associated with structural heart disease
-
Heart Murmurs are found in up to 8% of asymptomatic newborns
- Even without signs of Congenital Heart Disease, 37% will be diagnosed with Congenital Heart Disease
- Of infants with murmur, 2.5% will have a Critical Congenital Heart Disease lesion requiring early intervention
- Age of murmur onset related to pathology
- Murmur onset at 24 hours of life: 8% pathologic
- Murmur onset at 6 months of life: 14% pathologic
- Murmur onset at 12 months of life: 2% pathologic
- References
III. Causes: Innocent Murmurs
-
Still's Murmur (Aortic Vibratory Systolic)
- Most common Innocent Murmur
-
Venous Hum of late infancy and early childhood
- Second most common Innocent Murmur
- Septal hypertrophy due to myocardial fat deposition
- 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
IV. Causes: Pathologic Murmurs
- Ventricular Septal Defect (VSD) 20-25%
- Atrial Septal Defect (ASD) 8-13%
- Patent Ductus Arteriosus (PDA) 6-11%
- Tetralogy of Fallot: 10%
- Pulmonary Stenosis: 9%
- Pulmonary Artery Stenosis: 7%
- Aortic Coarctation: 5-8%
- Aortic Stenosis: 5-6%
- Transposition of Great Vessels: 5%
- Mitral Valve Prolapse 4%
- Total anomalous pulmonary venous congestion (2-3%)
- Tricuspid Atresia: 1-2%
- Hypoplastic Left Heart: Rare
- Truncus Arteriosus: rare
V. HIstory
- See Congenital Heart Disease
- Past Medical History
- Acute Rheumatic Fever
- Multisystem Inflammatory Syndrome (or Kawasaki Disease)
- Genetic Syndrome
- See Congenital Heart Disease for associated conditions
- One major or 3 minor findings of Genetic Syndrome
- Teratogen Exposure in Pregnancy and other prenatal factors
-
Family History
-
Congenital Heart Disease
- Relative Risk increased to 3 to 24 if sibling has Congenital Heart Disease
-
Hypertrophic Cardiomyopathy
- Screening Echocardiogram in first degree relatives
- Sudden Cardiac Death (or unexplained death) in young relatives
-
Congenital Heart Disease
VI. Exam
- See Heart Murmur
- See Systolic Murmur
- See Diastolic Murmur
- See Congenital Heart Disease
VII. Signs: Innocent Murmurs
- 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)
- Sensitive
- Murmur accentuates with position changes, activity - see below
- Short duration
- Not holosystolic
- Single
- Isolated murmur without click, gallup or other extra heart sounds
- Small
- Murmur limited to small, focal distribution without radiation
- Soft
- Low amplitude (e.g. II/VI murmur)
- Sweet
- Non-harsh quality
- Systolic
- Limited to systole (Diastolic Murmurs are typically pathologic)
- Sensitive
- Accentuation maneuvers (Innocent Murmurs become louder in this position)
- Sitting forward
- Exercise or increased Heart Rate
- Fever
- Anxiety, Restlessness, or crying
VIII. Signs: Pathologic Murmur
- See Congenital Heart Disease
- Red flag general exam findings
- Evidence of Failure to Thrive
- Lethargy
- Cyanosis
- Shortness of Breath
- Parasternal heave or thrill
- Murmur radiates to back or neck (e.g. carotid arteries)
- Murmur increases in loudness on standing or with Valsalva Maneuver
- Auscultation (6 Cardinal signs of pathology)
- Harsh murmur
- Pansystolic murmur or Diastolic Murmur
- Loud Murmur Grade 3 or more
- Murmur at high Left sternal border
- Early or Midsystolic click or murmur
- Fixed Split S2, or S3 or S4 Heart Sounds
IX. Diagnosis: Innocent Murmur (all 4 criteria required)
- No abnormal physical findings
- No symptoms suggestive of Congenital Heart Disease
- No increased risk of Congenital Heart Disease by history
- See Above
- No first degree relative Family History of Congenital Heart Disease
- 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)
X. Management: Approach
- Murmurs in newborns and children under age 1 year
- Newborns are higher risk for Congenital Heart Disease (esp. Genetic Syndrome, first degree relative with CHD)
- Refer to pediatric cardiology (first week of life)
- Echocardiogram
- Murmurs in older children and teens
- An Innocent Murmur that definately meets all above criteria does not require further evaluation or referral
- Systolic Murmur without cardiopulmonary or Congenital Heart Disease findings
- Repeat exam (physiologic murmurs typically resolve by repeat exam)
- Other murmurs should be referred for evaluation by cardiology and/or Echocardiogram (depending on local protocols)
- Pediatric cardiology can often make diagnosis without Echocardiogram and may prevent unnecessary testing.
- An Innocent Murmur that definately meets all above criteria does not require further evaluation or referral
XI. Management: Pathologic murmur suspected
- Newborn to eight weeks
- See Congenital Heart Disease for evaluation
- Pediatric Cardiology Referral
- Do not create preconceived notions of evaluation
- Not every Pediatric Murmur will need Echocardiogram
XII. Management: Innocent Murmur suspected
- Trust skilled clinical evaluation
- Study of clinical exam by pediatric cardiolgists
- Exam is as accurate as Echocardiogram
- Exam is more accurate than Electrocardiogram
- Test Sensitivity: 96%
- Test Specificity: 95%
- Positive Predictive Value: 88%
- Negative Predictive Value: 98%
- Reference