The 7 S’s of Innocent murmur mnemonics

An innocent murmur is commonly found in children and usually disappears as the child grows older. Here, the heart with its valves is absolutely normal. Possible mechanisms are :

  • Hyperkinetic circulatory states in children due to increased heart rate, and
  • Increased resistance of the pulmonary vascular bed in children.

Key feature of Innocent Murmur

  • Soft
  • Systolic
  • Short
  • Sounds (S1 and S2) normal
  • Symptomless
  • Special tests normal (X-ray, EKCG)
  • Standing/Sitting (vary with position)
Key features of innocent heart murmur in child
Innocent Murmur Features

What is not an Innocent Murmur?
Learn more about innocent murmur vs pathological murmur

  • Diastolic murmurs
  • Loud murmurs, grade IV or above
  • Regurgitant (pansystolic) murmurs
  • Murmurs associated with a click
  • Murmurs associated with other signs or symptoms (e.g. cyanosis)
  • Abnormal second heart sound (fixed split or single)
Innocent murmur vs pathological murmur
Innocent murmur vs pathological murmur features

Types of Innocent Murmurs

Types of innocent murmur
Types of physiological murmur

Pulmonary ejection murmur

  • It is high pitched and is best heard with diaphragm of the stethoscope in the second left intercostal space (pulmonary area) with radiation to lower left sternal border and apex.
  • The murmur is usually ejection systolic and is heard at the beginning of systole or mid-systole.
  • It is heard more clearly in situations of increased cardiac output such as fever, anxiety, acute disease and post-exercise.
  • Most common in children and adolescents aged between 8 and 14, particularly those with pectus excavatum or kyphoscoliosis.

Vibratory murmur or Still’s murmur

  • Found in many school age children.
  • Best heard at the lower left sternal border or apex with wide radiation.
  • Murmur is usually ejection systolic or early systolic with a musical or twanging quality. It increases with the patient lying down and decreases in the erect posture.
  • The murmur might disappear on extension of the neck.

Supraclavicular arterial bruit

  • Best heard on the right side of the neck and louder above the clavicle than below it.
  • The murmur is usually ejection systolic or early systolic.
  • Murmur is mostly found in adolescents and young adults, and is low-pitched and low intensity

Venous hum (jugular venous hum; cervical venous hum).

  • Best heard at the root of the neck over the medial part of the supraclavicular fossa (just lateral to SCM) with the head turned in the opposite direction.
  • A continuous murmur that increases on sitting up.

Mammary souffle

  • Best heard at the right or left sternal border, extending from 2nd to 4th intercostal spaces.
  • Continuous murmur with systolic accentuation.
  • Occurs during late pregnancy and lactation.

Read more about How to describe a murmur


  2. Medicine: Prep Manual for Undergraduates, 3/e

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