Premature Junctional Contractions (PJCs) Lecture Notes

Introduction

• Presented by Nurse Sarah
• Focus on Premature Junctional Contractions (PJCs)

Definition

• PJCs are early contractions from a focal point around the AV Junction rather than the SA Node.
• Causes random early beats within the underlying rhythm.

Key Takeaways

1. PJCs are premature early contractions.
2. They have P-wave issues similar to junctional rhythms.

P-Wave Issues

• Possible characteristics of P-waves in PJCs:
  • Concealed: Hidden within QRS complex
  • After QRS complex
  • Before QRS complex:
    • If before, PR interval < 0.12 seconds
    • Inverted P-waves in leads aVF, II, III

Difference Between PJCs and Junctional Escape Beats

• PJCs: No pause before the contraction; occurs randomly.
• Junctional Escape Beats: A pause occurs before the junctional beat; compensates for slow SA node firing.

Characteristics of PJCs

• Overall rhythm is irregular due to PJCs.
• Underlying rhythm should be regular.
• Rates vary based on the underlying rhythm.
• P-waves in underlying rhythm should be normal.
• PR interval:
  • Underlying rhythm: Normal (0.12-0.20 seconds)
  • PJCs: May be absent or < 0.12 seconds
• QRS complex: Normal < 0.12 seconds but occurs early during PJCs.
• QT interval and T-wave should be normal.

Example of PJC

• Underlying rhythm: Normal sinus rhythm with PJCs.
• Observations:
  • Inverted P-wave close to QRS
  • Concealed P-wave within QRS

Causes of PJCs

• Increased automaticity of the AV Junction, often due to:
  • Digitalis toxicity
  • AV node injury (surgery, infection)
  • Congenital defects
  • Tobacco use
  • Electrolyte imbalances (K, Ca, Mg)
  • Oxygen deprivation (myocardial infarction)
  • Hypoxia
  • Natural occurrence in some patients.

Treatment of PJCs

• Typically harmless; concern when frequent.
• Symptoms of concern include:
  • Chest pain
  • Palpitations
  • Fluttering in the chest
  • Low blood pressure
• Evaluate potential causes using the "Junction" pneumonic.
• Educate patients on modifiable factors:
  • Smoking cessation
  • Limiting alcohol intake
  • Avoiding caffeine
  • Balancing electrolytes
• Assess medication history for diuretics or digitalis.
• For patients on digoxin, notify the healthcare provider and check levels (normal: 0.5-2 ng/mL).

Antidote for Digoxin Toxicity

• Digifab

Conclusion

• Review of PJCs, their characteristics, causes, and management.
• Free quiz available for self-assessment in the description.