Paediatric Murmurs and ECG interpretation

Introduction

• 1% of children in developed countries have congenital heart disease
• Risk in sibling is 1-3%
• Detailed history of FHx, antenatal infections/drugs and association of any symptoms with activity is crucial
• Peripheral pulses, hepatosplenomegaly and general appearance are paramount
• If a thrill is present = pathological murmur

Split heart sounds

• Normally only hear split S2 during inspiration at upper left sternal edge
• Fixed splitting (same in inspiration and expiration) is seen in ASD
• S3 heard in 20% of normal children
• Clicks in early systole = Aortic or pulmonary stenosis

Murmurs

• Timing – systolic, diastolic, continuous
• Localisation
• Loudness (1-6)
• Character – Ejection, pansystolic, early/mid/late diastolic
• Radiation

Murmur grading

• 1 – Soft
• 2 – Slightly louder
• 3 – Loud with no thrill
• 4 – Loud with thrill (DEFINITELY PATHOLOGICAL BEYOND 3)
• 5 – Loud with thrill and heard with stethoscope partially off chest
• 6 – Audible without stethoscope

Innocent murmurs

• Heard in 50% of school-age children and even more in infants
• Normal or increased flow through normal heart and vessels
• Four characteristic types
  • Vibratory (Still’s murmur)
    • Short mid-systolic at left sternal border. Vibratory character. Often softer when child stends or extends neck and louder when lying supine.
  • Pulmonary flow murmur
    • Soft blowing murmur over pulmonary area. Difficult to differentiate from ASD or pulmonary stenosis
  • Carotid bruit
    • Rough ejection systolic murmur over base of neck but softer below the clavicle
  • Venous hum
    • High-pitched blowing continuous murmur over neck. Disappears when lies flat or when neck veins gently compressed

Changes with posture

• Most innocent murmurs get less intense with standing
• Most pathological murmurs do not change with positioning
• HOCM gets louder with standing

ASD vs innocent

• Probably the most important distinction as is most often confused
• Distinguishing features of ASD
  • Increased praecordial activity (palpable)
  • Wide split fixed S2
  • Does not change with standing

Features that increase likelihood of pathological cardiac disease

• Symptoms e.g. chest pain, poor feeding, sweating, poor growth
• FHx of Marfan’s or sudden death in young people
• Malformation e.g. Down’s syndrome
• Increased praecordial activity
• Decreased femoral pulses
• Abnormal S2
• Clicks
• Loud or harsh murmur
• Increased or no change in intensity when patient stands

Murmurs to refer

• Symptoms indicating cardiac disease
• Abnormal heart sounds (fixed splitting for instance)
• Murmur not definitely innocent in nature
• Murmur with thrill or grade 4 intensity +

ECG interpretation

• Common normal findings
  • Sinus arrhythmia
  • High QRS amplitude
  • TWI in all leads at birth, V1-2 only by 10yo (may persist in females and dark skinned people)
  • Relative RVH until 6mo
  • RBBB more common
  • Normal axis for age
    • <1 week: +60 to 190 degrees
    • 1-3 weeks: +65 to 160
    • 1-2 months: + 30 to 110
    • >2 months: +5 to 100
  • Shorter PR and QRS until 16yo
  • Prolonged QTc <490ms at 0-6mo and <440ms in older children
  • Early repolarisation
  • J point depression

• Axis
  • At birth +60 to +180 degrees, at 1 year +1 to +100 and at 10 years +1 to +130 degrees
• Atrial enlargement
  • Right atrial enlargement – Peaked P wave >2.5mm
  • Left atrial enlargement – P wave >0.08s
• Ventricular enlargement
  • RVH: 
    • R >S in V1 after 1 week and/or T wave upright in V1 after 1 week
    • S in V6 >15mm at 1 week, 10mm at 6mo and 5mm at 1 year
  • LVH:
    • S in V1 + r in V6 >30mm to 1 year or >40mm after 1 year

Last Updated on November 22, 2021 by Andrew Crofton