A junctional rhythm occurs when the AV node takes over as the primary pacemaker because either the SA node failed or the AV node blocked the atrial impulse.

Junctional Rhythm

• Rate: 40-60 bpm
• Rhythm: Regular
• P Waves: Absent, inverted or after the QRS
• PR Intervals: Not measurable, unless P wave is inverted and present
• R-R Intervals: Equal
• QRS Complexes: Normal and after each inverted P wave, if present

Accelerated Junctional Rhythm

• Rate: 60-100 bpm
• Rhythm: Regular
• P Waves: Absent, inverted or after the QRS
• PR Intervals: Not measurable, unless P wave is inverted and present
• R-R Intervals: Equal
• QRS Complexes: Normal and after each inverted P wave, if present

Junctional Tachycardia

• Rate: > 100 bpm
• Rhythm: Regular
• P Waves: Absent, inverted or after the QRS
• PR Intervals: Not measurable, unless P wave is inverted and present
• R-R Intervals: Equal
• QRS Complexes: Normal and after each inverted P wave, if present

Read the Junctional Rhythm: A comprehensive overview article to learn more about junctional rhythms.