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ECG library

Second-degree AV block, Mobitz II

advanced
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

  • Dropped beats without PR prolongation
  • Wide QRS
  • No warning before the drop

Learning points

  • Mobitz II fails without warning and can fall into complete heart block; it earns pacing.
  • The PR that never changes is what separates it from Wenckebach.

Connected