Innocent pediatric murmurs

(Redirected from Innocent Murmurs (Peds))


Clinical Features

  • Goal to distinguish innocent (benign) murmurs from clinically significant pathology
  • Red flag features that may point to pathology, not innocent murmurs:

Differential Diagnosis

Valvular Emergencies


  • Most innocent murmurs are
    • Not holo or diastolic
    • Not >grade III
    • Hockey stick dist
    • Normal S1 & S2



  • Mid-Systolic, best at left lower sternal border, likely from harmonic vibrations of LV outflow tract (chordae tindinae)
  • All ages, particularly young school age
  • Low pitch, musical
  • Decreased with inspiration, sitting, standing. Not a VSD- not regurgitant or with thrill

Innocent Pulmonary Flow Murmur

  • Systolic best at left upper sternal border, minor turbulence in RV outflow tract and main pulmonary artery
  • Often infants and preschool age. Higher pitched than still's, less musical
  • Not PS- no ejection click, no increased RV impulse. no wide s2 split
  • Not Pulm M of ASD, no fixed splitting, no diastolic tricuspid flow rumble, no increased RV impulse
  • Decreased on inspiration/sitting/standing

Innocent Pulmonary Branch Murmur of Infancy

  • Systolic ejection murmur from turbulence in pulmonary artery branches (one or both)
  • Medium pitch
  • Physiologic in neonates, becoming audible at L,R,B USB between 0-2wks
  • Transmits well to back and axilla. common in premature; disappears early in infancy
  • Not PS- no ejection click, no increase in RV impulse

Supraclavicular Bruit

  • Systolic ejection murmur of medium pitch from physiologic turbulence of carotid/subclavian and heard at base of neck
  • Can be palpable. Disappears on hyperextension of shoulders
  • Not AS which is loudest at URSB with systolic thrill, sometimes with click

Venous Hum

  • Continuous murmur from turbulent flow in SVC heard at L,R,or B infraclavicular position while sitting/standing
  • Not PDA (bounding pulse, systolic>diastolic sound) or AV malformation
  • Disappears in recumbent position, rotation of head, by pressure at jugular

Mammary Souffle

  • Blood flow in A and V to engorged breast
  • Systolic or continuous, disappears with stethoscope pressure

Cardiorespiratory murmur

  • High pitched cooing, anywhere, but especially apex
  • Breath sound so not timed to heart, disappear when holding breath


See Also