Accelerated Junctional Tachycardia

Aka: Accelerated Junctional Tachycardia, Junctional Tachycardia, Junctional Rhythm

1. Causes
   1. Acute Coronary Syndrome
   2. Digoxin Toxicity (esp. with underlying Atrial Fibrillation)
   3. Beta Adrenergic ReceptorAgonists
   4. Myocarditis
   5. Cardiac Procedures or Surgery
2. Findings: Junctional Rhythm
   1. Junctional Escape Rhythm
      1. Normal intrinsic junctional rate is 40-60 bpm
      2. Accelerated Junctional Rhythms are faster than 60 bpm
   2. Accelerated Junctional Rhythm (AJR)
      1. Rate 60-100 bpm (faster than intrinsic rate)
   3. Accelerated Junctional Tachycardia
      1. Rate >100 bpm
3. Findings: P Waves
   1. Timing
      1. P Waves may be subtle or absent
      2. Retrograde P Waves may follow QRS
      3. Retrograde P Waves may precede QRS
         1. Typically PR is too short (<120 ms) to be sinus rhythm
   2. Configuration
      1. Retrograde P Waves are inverted in inferior leads (II, III, avF)
      2. Retrograde P Waves are upright in lead V1 and aVR
4. Types
   1. AV Nodal Reentrant Tachycardia (AVNRT)
      1. Accessory pathway related re-entrant loop
   2. Automatic Junctional Rhythm
      1. Increased AV Node automaticity
5. Management: Accelerated Junctional Tachycardia
   1. See Supraventricular Tachycardia Management
   2. Typically does not respond to Vagal Maneuvers
   3. Diltiazem or Metoprolol for rate control (may convert to sinus rhythm)
6. Resources
   1. Burns (2021) Accelerated Junctional Rhythm, Life in the Fastlane
      1. https://litfl.com/accelerated-junctional-rhythm-ajr/
7. References
   1. Mattu (2018) Crit Dec Emerg Med 32(9): 12
   2. Mattu (2022) Crit Dec Emerg Med 36(9): 17