junctional rhythms
Dysrhythmias Sustained or Originating in the AV Junction
dysrhythmias
– Premature Junctional Contractions
– Junctional Escape Complexes and Rhythms
– Accelerated Junctional Rhythm
– Paroxysmal Junctional Tachycardia
-Inverted, Buried, or Retrograde P Waves in Lead II
– PRI of <0.12 Seconds
– Normal QRS Complex Duration
junctional complexes
- can be:
- inverted in front of the QRS (p wave) -> depolarizes atria from the bottom up bc it comes from the AV node
- buried within the QRS
- inverted behind the QRS
- timing is can different bc there is no delay between contractions when impulses come from the AV node
premature junctional contractions (PJC)
- rate depends on underlying rhythm
- rhythm depends on underlying rhythm
- pacemaker site is the ectopic focus in the AV junction
- P waves- inverted, may occur after the QRS
- PRI- normal if P occurs before QRS
- QRS is usually normal
- p wave can be absent in one complex
premature junctional contractions: etiology, clinical sig, treatment
- etiology- single electrical impulse originating in the AV node
- may occur with us of caffeine, tobacco, alcohol, sympathomimetic drugs, ischemic heart disease, hypoxia, or digitalis toxicity, or may be idiopathic.
- Clinical Significance- Limited, frequent PJCs may be precursor to other junctional dysrhythmias.
- Treatment- None usually required.
junctional escape complexes and rhythms
- rate- 40-60
- rhythm- irregular in single occurrence, regular in escape rhythm
- pacemaker site- AV junction
- p waves- inverted, may occur after QRS
- PRI- normal if p occurs before QRS
- QRS usually normal
junctional escape complexes and rhythms: etiology, clinical significance, treatment
- Etiology- Results when the AV node becomes the pacemaker.
- Results from increased vagal tone, pathologically slow SA discharges, or heart block.
- Clinical Significance- Slow rate may decrease cardiac output, precipitating angina and other problems.
- Treatment- None if the patient remains asymptomatic.
- treat symptomatic episodes with atropine or pacing as indicated
difference between premature and junctional escape complexes
- only the beat
- for premature the beat is happening early
accelerated junctional rhythm
- rate- 60-100
- rhythm- regular
- pacemaker site- AV junction
- p waves- inverted, may occur after QRS, buried
- PRI- normal is p wave is before QRS
- QRS normal
accelerated junctional rhythm: etiology, clinical sig, treatment
- Etiology- Results from increased automaticity in the AV junction.
- Often occurs due to ischemia of the AV junction.
- Clinical Significance- Usually well tolerated, but monitor for other dysrhythmias.
- treatment- None generally required in the prehospital setting
junctional tachycardia
- rate- > 100-180
- rhythm- regular
- pacemaker site- AV junctions
- p waves, inverted, may occur after QRS, buried
- PRI- normal if p waves occurs before QRS
- QRS- normal
junctional tachycardia: etiology, clinical sig, treatment
- Etiology- Rapid AV junction depolarization overrides the SA node.
- Occurs with or without heart disease.
- May be precipitated by stress, overexertion, smoking, or caffeine ingestion.
- Clinical Significance- May be well tolerated for brief periods.
- Decreased cardiac output will result from prolonged episodes, which may precipitate angina, hypotension, or congestive heart failure
> 100
junctional tachycardia
