Accelerated Junctional Rhythm
cautionLead II
25 mm/s10 mm/mV
HR
72
bpmRR
833
msQT
323
msRR
833
msPR
-123
msQRS
105
msQT
323
msQTc
343
msAccelerated Junctional Rhythm
An automatic focus in the AV junction firing faster than its intrinsic escape rate (60–100 bpm), overtaking the SA node. Same morphology as a junctional escape rhythm, only faster. Classic with digoxin toxicity, inferior MI, or post-cardiac surgery.
Recognition· 4
- Regular narrow QRS at 60–100 bpm
- Absent, inverted, or buried P waves
- Same shape as junctional escape, only faster
- Think digoxin toxicity / inferior MI
Mechanism
A junctional focus speeds up and takes over from the SA node
An enhanced automatic focus in the AV junction fires above its intrinsic 40–60 bpm escape rate. Because it outpaces the SA node, it becomes the dominant pacemaker while keeping the narrow QRS and retrograde P of a junctional beat.
Findings· 2
- Regular narrow-complex rhythm at 60–100 bpm.
- P waves absent, inverted (retrograde), or buried — retrograde P is negative in II/III/aVF and may fall just before, in, or after the QRS.
Clinical Impact
Marker of digoxin toxicity
↓Seen with inferior MI and after cardiac surgery
↓Loss of AV synchrony can reduce cardiac outputRISK
Usually a clue to digoxin, ischaemia, or electrolytes
Management· 2
1
Primary Treatment
Treat the underlying cause (hold digoxin, correct electrolytes, manage ischaemia).
2
Additional Options
Rarely needs direct rhythm treatment.