Junctional Rhythms

• Rhythms originate in the AV junction
• Impulses originate close to the AV node, not in the AV node itself
• Heart rates vary from slow to fast
• Three areas in which the impulses can originate in the AV junction: high, low, and mid

Junctional Rhythm

• Rate: 40-60
• Regularity: Regular
• P waves: Inverted or absent
• PR: <0.12 seconds if P wave precedes QRS
• QRS: <0.12 seconds
• Cause: Vagal stimulation, hypoxia, sinus node ischemia, heart disease
• Adverse effects: Potential for decreased cardiac output at slower heart rates
• Treatment: Atropine; consider oxygen; hold bradycardia-inducing medications

PJC

• Rate: Can occur at any rate
• Regularity: Regular but interrupted by premature beat
• P waves: Inverted or absent
• PR: 0.12 seconds if P wave precedes QRS
• QRS: <0.12 seconds
• Cause: Stimulants, hypoxia, heart disease, nicotine
• Adverse effects: Usually none
• Treatment: Treat the cause

Junctional Bradycardia

• Rate: <40
• Regularity: Regular
• P waves: Inverted or absent
• PR: <0.12 seconds if P wave precedes QRS
• QRS: <0.12 seconds
• Cause: Vagal stimulation, hypoxia, sinus node ischemia, heart disease
• Adverse effects: Decreased cardiac output
• Treatment: Atropine, pacemaker, oxygen; hold bradycardia-inducing medications

Accelerated Junctional Rhythm

• Rate: 60-100
• Regularity: Regular
• P waves: Inverted or absent
• PR: <0.12 seconds if P wave precedes QRS
• QRS: <0.12 seconds
• Cause: Heart disease, stimulants, caffeine
• Adverse effects: Usually none
• Treatment: Usually none needed (remove the cause)

Junctional Tachycardia

• Rate: >100
• Regularity: Regular
• P waves: Inverted or absent
• PR: <0.12 seconds if P wave precedes QRS
• QRS: <0.12 seconds
• Cause: Digitalis toxicity, heart disease, stimulants
• Adverse effects: Decreased cardiac output at faster heart rates
• Treatment: Beta-blockers, calcium channel blockers, adenosine; consider oxygen