Innocent pediatric murmurs

  • 72% of all school-age children have innocent murmurs
  • Congenital heart disease 0.8% of live births
  • Still's- mid-Systolic, best at LLSB, likely from harmonic vibrations of LV outflow tract (chordae tindinae). All ages, particularly young school age. Low pitch, musical. Decr. with inspiration, sitting, standing. Not a VSD- not regurgitant or w/ thrill. VSD - HSM
  • Innocent Pulmonary Flow Murmur- systolic best at LUSB, minor turbulence in RV outflow tract & main pulm. a. Often infants and preschool age. Higher pitched than still's, less musical. Not PS- no ejection click, no incr. RV impulse. no wide s2 split. Not Pulm M of ASD, no fixed splitting, no diastolic tricuspid flow rumble, no incr. RV impulse. Decr. on inspiration/sitting/standing.
  • Innocent Pulmonary Branch Murmur of Infancy- SEM from turbulence in Pulm. A. branches (one or both). Med pitch. Physiologic in neonates, becoming audible at L,R,B USB btwn 0-2wks; transmits well to back and axilla. Common in premature; disappears early in infancy. Not PS- no eject click, no incr. RV impulse.
  • Supraclavicular Bruit- SEM of med 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 turb.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 esp apex. Breath sound so not timed to heart, disappear when holding breath.


  • Check height and weight- L-to-R can cause decr., but are usually symptomatic.
  • Color- so, so but cynanosis of hands,feet,perioral on exertion.
  • Feeding- fatigue or short feeding times for infants- perspiring, grunting, coughing, tachycardia while feeding. Severe CHF may show at rest deep breathing with dyspnea w/ distress.
  • Enlarged heart (ie ASD) can cause bulging of chest
  • Older kids- activity causing dyspnea/cyanosis- keeping up with peers, grunting, coughing, tired from stairs. Syncopal/presyncopal, incr fatigue, palpitations/angina can occur with IHSS
  • Yet older- Aortic valve with rheumatic fever,myocarditis (h/o URI), endocarditis (IV drug use)
  • Preg Hx- Diabetes M (ASD, coarctation of aorta, cardiomyopathies), CMV, Coxsackie B5, warfarin, antiseizure, EtOH (ASD,VSD), prematurity (PDA)
  • Worry when- fam hx of IHSS/sudden death & prominent apical thrust indicates LVH
  • S1 & S2 are not normal or are obscured
  • Murmur is not musical or vibratory
  • most innocent murmurs are
    • not holo or diastolic
    • not >grade III
    • hockey stick dist
    • normal S1 & S2

See Also

Heart Murmurs