Matters of the Heart - Junctional Rhythms and Beats
Junc in the trunk? Let’s talk about Junctional Rhythms and beats!
Why should you spend your time learning about Junctional Rhythms? Are they even that common? Well…. they can be. There isn’t a vast amount of epidemiological information on Junctional Rhythms, but we do know that they tend to be common in people suffering sick sinus syndrome and in young and athletic individuals (Junctional Rhythms).
The things is, Junctional Rhythms have popped up multiple times in my nursing career, while working on the floor and in the ICU. Having a basic understanding of Junctional Rhythms gives you the ability to plan care for your patients, more effectively.
An interesting thing about Junctional rhythms, is that they can be fairly easy to remember once you understand the definition of a junctional beat and rhythm.
So, as always, we are going to keep this sweet and simple. Let’s go!
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What are Junctional rhythms?
Essentially , junctional rhythms are the result of electrical impulses, in the heart, that stem from somewhere other than the Sinoatrial (SA) Node that we talked about in sinus rhythms post.
In the case of junctional rhythms, the impulses are originating from the Atrioventricular (AV) node junction, the junction in junctional rhythm. So, if you remember from our review of sinus rhythms, typically, when impulses originate from the primary pacemaker of the heart, the SA node, a P-wave will usually be present on the ECG. So, if the impulse is originating from the the AV node, what do you think happens to the P-wave????
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You guessed it, it’s not there!!!! Well….. at least sometimes. Other times the P-wave may be present, but be inverted or come after the QRS complex.
In cases where the P-wave is present, but inverted, the PR interval is typically shortened, less than the typical .12 we associate with PR intervals.
In many cases, particularly when the p-wave comes after the QRS complex, the p-wave may be hidden inside of the QRS complex, thus no distinguishable P-wave will be visible on the ecg.
Now, it should be noted that there a different types of junctional issues/rhythms.
Want to see what they look like?
Let’s start with Premature Junctional Contractions, or PJC. What is a PJC?
A PJC is a beat that originates from the AV node junction, before a sinus beat, thus disrupting the underlying rhythm. Typically there is either no p-wave because it’s hidden in the QRS complex, or the P-wave may be inverted and appear before the QRS complex.
Here’s a picture of an ECG/EKG strip, showing 2 junctional beats.
(Source)
Note: This strip includes Normal rhythms and complexes, but include 2 PJCs. The second and 7th QRS complexes are missing P-waves, and are PJCs. This is SR with 2 PJC. There may also be a pause after the PJC.
When a there is a regular repetition of PJCs or junctional beats, the ECG/EKG is referred to as a “Junctional Rhythm”. The rate for a junctional rhythm typically has a rate between 40 and 60 bpm, as seen below.
(Source)
Next, let’s talk about Junctional Escape Rhythms.
What are Junctional escape rhythms?
Junctional Escape Rhythms are easy to talk about after the standard Junctional Rhythm because…….they are the same thing…. Haha! Surprise!
The terms Junctional Rhythm (a sustained run of PJCs or Junctional beats) is used interchangeably with Junctional Escape Rhythm.
So on to the next!
Accelerated Junctional Rhythm.
What is an accelerated Junctional rhythm?
So an Accelerated Junctional Rhythm is exactly what the name means, a junctional rhythm that has a rate that is higher than the typical 40-60 bpm. Thus, a junctional rhythm is considered “accelerated” when the rate is between 60-100 bpm.
Here’s a picture of an accelerated Junctional rhythm.
(Source)
Note: The rate (count the QRS complexes) is approximately 70 beats per minute.
It’s worth mentioning that the appearance of the QRS complexes can change. According to what lead you are view the ECG/EKG. In some cases or in some ekg leads, the QRS complex is negatively deflected (with the long spiked part point down instead of up, lol).
Regardless of the deflection of the QRS complexes, accelerated Junctional rhythms can sometimes be mistaken for accelerated idioventricular rhythm, a rhythm that can lead to more serious issues if unresolved.
Below is a image for reference, Note the difference in the size and shape of the QRS complexes.
(Source)
Note: Unlike an accelerated Junctional rhythm, which has an expected heart rate from 60-100 bpm, accelerated idioventricular rhythms have a wider range, anywhere from 40–100 bpm. The interventions and treatment of accelerated Junctional rhythms and accelerated idioventricular rhythms can be different, thus, knowing the difference can be important. Always as a more experienced provider to assist when you are unsure.
Last but not least, let’s talk about Junctional Tachycardia
What is Junctional Tachycardia?
Junctional Tachycardia is defined as a 3 or more successive PJCs (see above), with a ventricular rate greater than 100 bpm. The rate can be anywhere from 100 to 200bpm.
Here’s a picture.
(Source)
Signs and symptoms
Outside of the ECG/EKG manifestations, what are the signs and symptoms of Junctional rhythms and beats?
PJC
Underlying rhythm is likely regular and the pulse rate is most likely on the lower end of normal or it is actually bradycardic in nature.
When it comes to the occasional PJC, there are typically no symptoms.
Possible feelings of palpitations or skipped beat.
With more frequent PJCs, hypotension.
Junctional Rhythm/Junctional Escape Rhythm
Slow, yet regular, pulse rate (40-60 bpm)
Persistent rates that are significantly below 60 bpm
Decreased Cardiac Output
Hypotension
Syncope
Mental Status changes
Changes in vision
Weak pulse upon palpating pulse points
Accelerated Junctional Rhythm
Possibly no symptoms
Normal pulse rate and regularity to the overall rhythm
Decreased Cardiac Output and associated symptoms (see above).
Junctional Tachycardia
Pulse rate above 100 bpm
Decreased Cardiac Output and associated symptoms (see above).
What causes junctional rhythms and beats?
Cardiomyopathy
Digoxin toxicity is a common cause of Junctional activity
Heart failure
Sick Sinus Syndrome
Valvular disease
Electrolyte imbalances
Cardiac Surgeries and procedures
Rheumatic Heart Disease
Myocardial Infarctions
Now, how do we fix this?
Treatment: Meds/Tests/Imaging for Junctional Rhythms
The treatment of Junctional rhythms focus more on isolating the underlying issue, and not on the rhythm itself.
Junctional Escape Rhythm is a way the heart avoids a more dangerous rhythm (idioventricular rhythms) and a halting of ventricular activity.
Medications
Atropine
More Severe Cases, where the physiological response to atropine is insufficient to create adequate cardiac output other vasoactive drugs may be warranted
Transcutaneous, Transvenous and Permanent pacemakers
Correcting electrolyte imbalances
Supplemental Oxygen
In Junctional Tachycardia, more accelerated rates may warrant the administration of beta blocker or calcium channel blockers to slow the rate.
In some cases of Junctional Tachycardia, Adenosine may be warranted.
If the course of the Junctional tachycardia is Digoxin Toxicity, the administration of a Digoxin reversal or binding agent, such a Digibind is warranted.
Cessation of Digoxin if it is believed to the the cause of the Junctional Escape Rhythm or frequent PJCs.
Nursing interventions/Considerations for Junctional Rhythms
A primary set-back and manifestation of untreated Junctional rhythms and frequent PJCs is a decrease in cardiac output, which means things like blood pressure and consciousness can begin to decline as the issue progresses.
Remember, the terms Junctional Rhythm and Junctional Escape Rhythm are used interchangeably and represent a sustained rhythm of Junctional beats.
Junctional Rhythms and beats tend to occur in bradycardia or slower rhythms.
Junctional escape beats can sometimes be a normal finding in young children or in healthy and physically fit adults.
Junctional Escape Rhythms help the heart escape more volatile and dangerous rhythms and states, thus a junctional escape rhythm should not be suppressed, but treatment should focus on isolating underlying causes for the condition.
If a p-wave is visible in any junctional rhythm or beat, it is typically inverted and the PR interval (PRi) is shortened, less than .12.
There you go! We’re done! It wasn’t as bad as you thought it would be, was it?
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Sources
Practical Clinical Skills ECG Library
ECG Interpretation Made Incredibly Easy! Pocket Guide, Third Edition
Critical Care Nursing Demystified
Disclaimer: This material should be used to supplement your understanding of the cardiovascular system. Any use of the information given in this post series is at your own risk and should be verified prior to making it a part of your nursing practice. There may be affiliate links associated with some products but we promise that we will never recommend anything that we don’t use ourselves.
