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Junctional Escape Rhythm

caution
Lead II
25 mm/s10 mm/mV
Heart rate
72bpm
RR
833ms
QT
358ms

Junctional Escape Rhythm

A protective escape rhythm originating from the AV junction when the SA node fails to fire or SA impulses fail to conduct. The AV junction's intrinsic rate is 40–60 bpm. This prevents asystole when higher pacemakers fail.

Mechanism

A protective escape rhythm originating from the AV junction when the SA node fails to fire or SA impulses fail to conduct. The AV junction's intrinsic rate is 40–60 bpm. This prevents asystole when higher pacemakers fail.

Findings· 3
  • Regular narrow-complex rhythm at 40–60 bpm.
  • P waves absent, inverted (retrograde), or buried in QRS.
  • If visible, retrograde P waves are negative in leads II, III, aVF and may occur immediately before, during, or after QRS with PR <0.12s.
Clinical Impact

Usually benign escape mechanism. Indicates sinus node dysfunction or high-grade AV block. If symptomatic (dizziness, hypotension from slow rate), may require atropine or pacing. Treat underlying cause.

Differential· 2
Sinus Bradycardia

Both slow regular rhythms. Sinus brady has upright P waves before each QRS.

Complete Heart Block

Junctional escape in complete block shows independent P waves. Isolated junctional has no atrial activity.