Heart & Cardiology/Junctional Rhythms



What is the significance of junctional and accelerated junctional rhythms?...From readings, seems like Digitalis Toxicity is a very common reason for junctional rhythms, but isn't that a mediciation?....I do not take anything other than 10ml. of generic Lipitor in effort to raise HDL...

Since 2009, I've had 2 normal echo's and a normal CMRI..A 48 hr. Holter in 2012 showed sinus and junctional rhythms...Also, a recent 30 day event study showed accelerated junctional rhythm when i submitted readings....But the EP didn't seem concerned, i do feel pretty good, (I'll feel flutters,skips often) but I;m never hampered in doing any activities....I never feel light-headed nor have i ever had syncope.....

It seems like my heart is fine structurally, yet electrically I'm a mess, if that makes sense...

Thank You


The heart is an electrical organ that has a sophisticated network of highly specialized cells to distribute the electrical signals evenly over the heart.  When this system becomes disrupted arrhythmias, such as the one you are describing, can occur.  Normally the electrical impulse originates in a group of cells at the top of the heart known as the "sinus node", then spreads over the upper chambers of the heart, and then must pass through a "relay station" known as the AV node before distributing across the bottom chambers of the heart.  Our nervous system can control your heart rate so that, for example, if you start to do exercise, your nervous system tells the heart it needs to speed up.  Sometimes when people have really ""overstimulated" nerve responses (such as increased vagal tone), the order in which the electrical signal propogates can become reversed, such that the signal originates in the AV node instead of the sinus node. I realize i may have been a little technical but i'm sure you have read up on some of this! This is one type of junctional rhythm.

Treatment of junctional and accelerated junctional rhythm depends on the underlying cause and also the symptoms caused. Like you mentioned there are well known underlying causes such digitalis toxicity, structural heart disease, disease of the cardiac conduction system. The first step in treatment is to rule out these causes, and in your case the normal MRI and echo have ruled out underlying structural heart disease which is reassuring. Also reassuring is that your EP is not concerned meaning that there is unlikely to be any concerning underlying conduction system disease. In that case you would only likely be treated for symptoms such as dizziness, passing out etc. Its good that you are not really symptomatic from this, and you feel good and have no significant limitation. Therefore your EP, who knows your case well, feels that you don't likely warrant specific treatment for this.

Hope that was helpful,

[an error occurred while processing this directive]---------- FOLLOW-UP ----------

QUESTION: Hi Dr Ahmed,

Thank you for your reply....One quick follow-up...Are the junctional rhythms a pre-cursor to eventually having heart block, or A-Fib?....Or is that not the case..


The majority of people with an accelerated junctional rhythm are found to have some sort of heart disease upon further testing.  In your case, you have been found to have no heart disease, which is less common. Therefore, the answer to your question is a bit complex because it depends upon the specifics of your medical history and the exact rhythm that you were found to have (there are different forms of junctional rhythm).  I am also assuming that the tests you already had truly ruled out any existing cardiac abnormalities which seems to be the case.  

Even knowing the details of your medical history, it is still difficult to answer because accelerated junctional rhythms in normal hearts are fairly rare and thus not well studied. The good thing is they are not automatically classified as being dangerous.  As I stated before, it appears that based on the information you have given me, you probably have an accelerated junctional rhythm due to high vagal tone.  If you are a relatively young person and have no other medical problems, this is probably a benign condition and is less likely to progress to a more serious electrical problem.  However, if you are older, a smoker, overweight with high blood pressure and diabetes, you are already at risk of developing heart disease and thus would be at increased risk of having future problems with the electrical (and mechanical) systems of your heart.  Anything in between makes it more difficult to say.

The best thing to do is to continue to be monitored by a physician, pay attention to risk factors such as smoking, cholesterol, exercise, diet etc.. If you develop symptoms that are related to the arrhythmia then the issue can be revisited as required.

Hope that was helpful,

---------- FOLLOW-UP ----------

QUESTION: Hi Dr. Ahmed,

One final thing about vagal tone....While I'm fit, i walk about 30 miles a week...5"10, 153 lbs...But I'm certainly no olympic athlete....I certainly don't think I have the so-called "athletes heart", wouldn't that pertain more to marathon runners, olympic athletes, etc...Is high vagal tone brought on by stress?....My father died of a heart attack long time ago (he was 48, I'm 44 now), and my mom died 3 yrs afo...Perhaps stress over that has caused some of the rhythm issues...

My episodes of junctional rhythms (junctional tachycardia, accelerated JR) were first noticed in early 2012....But the CMRI i had was done in Nov 2012 and the summary from that report read:

"Normal LV systolic function, LVEF 57%...No myocardial infaraction, scarring, fibrosis, or infilitrative heart disease found on late gadollinum enhancement...No structrual heart defect is demonstrated"...

I guess it "could" be issue of cornary arteries causing the Junctional rhythms?. but despite my HDL being tad low (30-34) range ALL other numbers are well within range (LDL is usually 70-90) and BP is normal...


There is a really large body of literature on the autonomic nervous system and autonomic tone and there are all sorts of interesting data on how well people do depending on different measures of activity of their autonomic nervous system (such as heart rate variability, resting heart rate, and heart rate recovery for example).  However, there is no real consensus on what to do about it other than treat whatever underlying diseases that the person may have.  Perhaps we will address this in a future post on our blog, because it would take quite some time to give a proper answer (http://www.ccjm.org/content/76/Suppl_2/S18.full).

Given the amount of exercise you do (30 miles a week is way more than most people) I would say that could explain at least part of your theorized high autonomic tone (this is not a bad thing).  Stress may certainly play a part as well (which could be a bad thing).  Either way, I wouldn’t spend too much time worrying about what it means for you, because at the end of the day the recommendations would be the same, which would be to do all you can to reduce your cardiovascular risk factors.  You do have a certain elevated genetic risk simply because of your father’s medical history, but there is nothing you can do about that.  Therefore you should control your blood pressure, control your weight, control your cholesterol, exercise, and eat a healthy diet.  It certainly sounds like you are already on track for these things and so I would keep doing them.  Apart from that, regular checkups with your doctor who knows you best are a must.  

Hope that was helpful,

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Mustafa Ahmed MD


Cardiology, Interventional Cardiology, Cardiac Surgery, Hypertension, Pulmonary Embolism, Structural and Valve Disease


Board Certification Internal Medicine and Cardiology Interventional and Structural Cardiology


Multiple Publications In High Quality Peer Reviewed Journals. Internationally Recognized.

MD from The Royal Victoria University of Manchester, England Medicine, Cardiology, Interventional Cardiology, Research Training - University of Alabama

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