Premature junctional complex

ECG 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, with ventricular response usually normal, so QRS complexes usually narrow
• If conduction abnormal, may have RBBB morphology

Clinical Significance

• Less common than PVCs or PACs
• Differentiate from WPW (short PR)
• 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