Junctional Rhythms

Things to Remember

●Junctional arrhythmias occur at the AV
node/bundle of His

○The SA node is suppressed and fails
to conduct

●This causes the electrical activity to the
atria flow backwards causing in an
inverted P wave (retrograde
depolarization)

**Sometimes atrial arrhythmias are mistaken for
junctional**

How to know the difference:
Look at the P-R interval

●Inverted P waves & normal P-R interval=
atrial

●Inverted P waves & <0.12 P-R interval=
junctional

PREMATURE JUNCTIONAL

COMPLEXES (PJC)

Early impulse that occurs before the next expected beat

P Wave could occur before, after or can be buried within the QRS complex

Causes: toxic levels of digoxin, caffeine, inferior wall MI, heart failure

JUNCTIONAL ESCAPE

●Impulse originating from the AV node (acting as a backup pacemaker

●Atria and ventricles receive the impulse simultaneously

●Absent or inverted P waves

●HR will not exceed 40-60 bpm (coming from the AV node)

○Can exhibit signs of reduced cardiac output due to lower HR and lack of
atrial kick

●Causes: sick sinus syndrome (group of heart issues that affect the SA node), electrolyte imbalance, digoxin toxicity, inferior wall MI

●Same as Junctional Escape, but the rate is 60-100
(absent or inverted P waves)

●Does not usually have signs of decreased cardiac output

●Causes: digoxin toxicity, hypokalemia, hyperkalemia,
inferior/posterior MI

JUNCTIONAL TACHYCARDIA

●Same as escape and accelerated but the HR is between 100-150
bpm (a form of SVT--discussed on next slide)

●Because of tachycardia, the patient is likely to experience
palpitations or fluttering

SUPRAVENTRICULAR TACHYCARDIA (SVT)

●No necessarily a junctional arrhythmia

●Included here because the impulse comes from above the
ventricles

●HR is >150 bpm

●P waves are not visible, P-R interval is unmeasurable