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ECG library

Right bundle branch block

core
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

  • QRS ≥ 120 ms
  • rSR' ('rabbit ears') in V1
  • Wide S in lateral leads

Learning points

  • RBBB leaves the early QRS untouched, so infarction Q waves remain readable.
  • New RBBB with hypoxia and tachycardia should raise pulmonary embolism.

Connected