Introducing the Junctional Rhythms
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Transcript of Introducing the Junctional Rhythms
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
For the Dental Hygienist
CHAPTERCHAPTER
Understanding EKGsA Practical Approach
9Introducing the Junctional Introducing the Junctional RhythmsRhythms
Copyright ©2010 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Introducing Junctional Rhythms
• Objectives– Discuss the origin of junctional rhythms– Recall the components of the electrical
conduction system– Identify premature junctional contractions,
including EKG characteristics– Identify a junctional escape rhythm, including
EKG characteristics
Copyright ©2010 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Introducing Junctional Rhythms
• Objectives (continued)– Identify an accelerated junctional rhythm,
including EKG characteristics– Identify a junctional tachycardia rhythm,
including EKG characteristics– Discuss the clinical significance of the
junctional rhythms
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Origin of Junctional Rhythms
• Rhythms that are initiated in the area of the AV junction are called junctional rhythms
• Although junctional rhythms are not considered to be lethal, or life-threatening, you should recall that patient assessment is the most important indicator of clinical significance
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Components of Electrical Conduction System of the Heart
• Electrical impulse originates in SA node
• Travels through atria via internodal pathways
• AV node, brief pause, bundle of His
• Right and left bundle branches
• Purkinje fibers into the ventricular musculature
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
P Waves in Junctional Rhythms
• Normally P waves are seen before each QRS
• Impulse in junctional rhythm is traveling away from (+) electrodes, P wave will be inverted or negative
• The P wave can be hidden in the QRS or follow the QRS complex
Impulse Direction
•The location of the impulse changes the position of the ‘P’ wave
•Impulse originates in AV Node and retrograde backward to SA Node
•Causing a negative deflection on ECG of ______ Wave?
•The impulse will follow normal route and ______ wave will be _______ deflected on the ECG?
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
The Premature Junctional Contraction (PJC)
• Are initiated from a single site in the AV junction and arise earlier than the next anticipated complex of the underlying rhythm
• If SA node depolarized by ectopic beat, a noncompensatory pause occurs and underlying rhythm is interrupted
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
The Premature Junctional Contraction (PJC)
• PJC can also cause compensatory pause, a pause that occurs after ectopic beat and underlying rhythm is uninterrupted
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Premature Junctional Complexes
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Premature Junctional Complexes
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Premature Junctional Contraction (Complexes) or PJCs
• PJCs are less common than PACs or PVCs
• As with all ectopic beats, it is easier to identify PJCs if rhythm is sinus or bradycardia
• When interpreting PJCs, you must also determine the underlying rhythm
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Junctional Escape Rhythms
• The SA node may fail to generate an impulse, or if rate falls below that of the AV node, then AV node will assume the role of pacemaker
• This ability is a safety feature
• Intrinsic rate of the AV node is 40-60
bpm
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Junctional Escape Rhythm
• Junctional escape beat – Isolated junctional beat occurs
• Junctional escape rhythm– Series of junctional escape beats occur,(sometimes termed junctional bradycardia
when rate < 40 bpm• Causes
– SA node disease, hypoxia, increased parasympathetic (vagal) tone, cardiac drugs, or complete heart block
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Junctional Escape Beats
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Junctional Escape Rhythm
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Accelerated Junctional Rhythms
• Caused by increased automaticity in AV junction, causes junction to discharge impulses at fast rate, then intrinsic rate (40-60 bpm)
• Rate is usually around 60 to 100 bpm
• Causes include– Hypoxia, digitalis intoxication, inferior wall MI,
and rheumatic fever
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Accelerated Junctional Rhythm
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Accelerated Junctional Rhythm
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Junctional Tachycardia Rhythms
• Rhythm that arises from AV junctional tissue at a rate of 100 to 180 bpm
• If observed to start or end abruptly referred to as paroxysmal rhythm
• It may be indistinguishable from supraventricular tachycardic rhythms
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
• Causes– Underlying ischemic heart disease,
frequent ingestion of stimulants, anxiety, hypoxia, Medications such as digitalis, or rheumatic heart disease
• Treatment– Aimed at identifying and treating the
underlying cause of the dysrhythmia
Junctional Tachycardia Rhythms
Junctional Tachycardia Rhythms
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Junctional Tachycardia
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Junctional Tachycardia
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Clinical Significance of Junctional Rhythms
• Premature Junctional Contractions– Based on frequency of their occurrence and
patient’s condition– Isolated PJCs are of minimal significance– Frequent (> than 6/min) more serious
dysrhythmias may develop– Management includes only close observation
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Clinical Significance of Junctional Rhythms
• Junctional Escape Rhythm – Based on patient’s heart rate and clinical
condition– Intrinsic rate of AV junction = 40 to 60 bpm– Watch for signs of compromise– If decreased perfusion observed, treat with
oxygen, and consider drug therapy– May be tolerated at 50 to 60 bpm
Copyright ©2010 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Clinical Significance of Junctional Rhythms
• Accelerated Junctional Rhythm– Generally well tolerated by patient– May suggest the possibility of digitalis toxicity– Patient must be carefully monitored for
occurrence of other, more serious dysrhythmias
Copyright ©2010 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458
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Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley
Clinical Significance of Junctional Rhythms
• Junctional Tachycardia Rhythm– May be well tolerated in healthy hearts– Not tolerated in patients with cardiac
compromise– May report feeling heart “running away or
fluttering”– Treatment based on patient’s clinical
appearance, signs, and symptoms