II. Mechanism

  1. Ectopic focus from the Atrioventricular Node (AV Node) or proximal Purkinje Fibers

III. Causes: Junctional Tachycardia

  1. Acute Coronary Syndrome
  2. Myocarditis
  3. Cardiac Procedures, Chest Trauma or Thoracic Surgery
  4. Radiation Therapy
  5. Inherited Channelopathy
  6. Medications
    1. Beta Adrenergic ReceptorAgonists
    2. Digoxin Toxicity (esp. with underlying Atrial Fibrillation)
    3. Clonidine
    4. Lithium

IV. 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 (Junctional Ectopic Tachycardia, JET)
    1. Rate >100 bpm (average rate 130)

V. 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

VI. Types

  1. AV Nodal Reentrant Tachycardia (AVNRT)
    1. Accessory pathway related re-entrant loop
  2. Automatic Junctional Rhythm
    1. Increased AV Node automaticity

VII. 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)

VIII. Resources

  1. Burns (2021) Accelerated Junctional Rhythm, Life in the Fastlane
    1. https://litfl.com/accelerated-junctional-rhythm-ajr/

IX. References

  1. Mattu (2018) Crit Dec Emerg Med 32(9): 12
  2. Mattu (2022) Crit Dec Emerg Med 36(9): 17
  3. Rivera-Moran, Vandersteenhoven and Brady (2025) Crit Dec Emerg Med 39(4): 15-7

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