Premature junctional complex

EKG Findings

• P wave be either:
  • Absent
  • Abnormal P wave with short PR < 120ms
  • "Retrograde P waves, which may be inverted in inferior leads
• PJC arrives before next sinus beat
• Followed by compensatory pause
• From AV node region and ventricular response usually normal, so QRS complexes narrow
• If conduction abnormal, may have RBBB morphology

Clinical Significance

• Less common than PVCs or PACs
• Differentiate from another more serious cause of short PR (WPW seen in image attached alongside PJCs)
• May be seen in healthy individuals with no clinical significance
• Or in pathology such as valvular disease, drug toxicity, electrolyte disorder

WPW with PJC underlined in red

Sources

• Amal Mattu. Mattu ECG Case: Feb 5 2012. Published Apr 9, 2012. UMEmergencyMed. https://www.youtube.com/watch?v=Sb8JozMnxpI.
• Burns E. Premature Junctional Complexes. LifeInTheFastLane. http://lifeinthefastlane.com/ecg-library/pjc/