Innocent murmurs and normal paediatric cardiovascular variants — viva

Stem

You are shown a thriving 4-year-old referred with a soft systolic murmur found at a preschool check. [1]

Examiner: Describe your approach to this child. [1]

Strong answer: I will confirm the child is thriving and asymptomatic — no colour change, breathlessness on feeding or exertion, syncope, squatting or poor growth. Then I will examine positionally, supine and upright, across all four classical areas and the back, assessing the murmur's timing, grade, location and posture effect, and explicitly checking the heart sounds, the splitting of S2, the femoral pulses and an oxygen saturation in room air. [1] [5]

Examiner (branch 1): You hear a soft vibratory systolic murmur at the lower left sternal edge that softens when the child sits up; S2 splits normally with respiration, pulses are normal and SpO₂ is 99%. What is your diagnosis? [3]

Strong answer: This is a Still's vibratory murmur — the commonest innocent murmur of children aged 2–7 years: soft, short, vibratory/musical, lower left sternal edge, softer when upright, with normal heart sounds, normal femoral pulses and normal saturation in a thriving asymptomatic child. [3]

Examiner (branch 2): Give three red flags that would have forced you to refer instead. [1]

Strong answer: Any diastolic, holosystolic or continuous murmur (other than a venous hum); a harsh, grade ≥3/6 murmur or a thrill; a fixed or widely split S2; abnormal femoral pulses or radio-femoral delay; symptoms such as failure to thrive, exertional intolerance, syncope or cyanosis; or a murmur radiating to the back or neck. [1] [2]

Examiner (branch 3): What would you tell the family, and what would you arrange? [1]

Strong answer: I would reassure them that the heart is structurally normal and the murmur is benign and will resolve with growth. I would arrange no echocardiogram, ECG or CXR, place no activity restriction, give no endocarditis prophylaxis, and offer routine dental care. I would document the specific innocent murmur and the reasoning, and safety-net to return if new symptoms appear. [1] [3]

Examiner (branch 4): How would your answer change if this were a 6-week-old infant? [2]

Strong answer: I would apply a much lower threshold. I would not label a neonatal or young-infant murmur innocent on first hearing, because neonatal murmurs carry a higher probability of structural disease and the transitional circulation changes the picture. I would refer to paediatric cardiology, measure a pulse oximetry to detect critical congenital heart disease, and arrange echocardiography. [1] [2]

Examiner (probe): Name the trap lesion that can mimic an innocent murmur. [2]

Strong answer: Atrial septal defect — the murmur is soft and pulmonary, but S2 is fixed and widely split, and the lesion is missed if you listen only to systole. Always check the splitting of S2. I would also feel the femoral pulses to exclude coarctation. [2] [6]