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ECG library

Congenital complete heart block

advanced3 days old· newborn

A newborn, day 2, whose mother has systemic lupus with anti-Ro antibodies. The fetal heart rate had been 'slow' on the last two scans. He is pink and feeding.

25 mm/s · 10 mm/mV · synthetic tracing
100%
IIIIIIaVRaVLaVFV1V2V3V4V5V6
II (rhythm)
Calipers:2000 ms50.0 small boxes30 bpm if R-RDrag the orange markers. One small box = 40 ms.

Key findings

  • Newborn ventricular rate near 50
  • P waves unrelated to the QRS
  • Narrow junctional escape

Learning points

  • A well newborn with a heart rate of 50 is a heart block until the ECG says otherwise; the mother's autoantibody status is the first question.
  • The decision that matters is pacing: a narrow escape above about 55 in a newborn without heart failure is watched; a rate below that, a wide escape, pauses, or a structurally abnormal heart move the child toward a pacemaker.
  • Fetal bradycardia on a scan in a mother with lupus or Sjogren syndrome is the same disease seen earlier.

Connected