WPW causing bradycardia?

[shaolinRX]

First off: Shout out to all the med students from a pharm. student!

Okay, so we're covering a brief glimpse into heart arrhythmias in class and I'm intrigued somewhat because I have a close friend with WPW syndrome. I didn't know much about it until this lecture, but from what I gather it is a condition where the patient has an extraneous bundle (bundle of Kent) that can result in tachycardia. My friend, however has never experienced any of the resultant tachycardia; in fact, she has quite the opposite effect --bradycardia (35-50bpm at night) and frequent palpitations. Has anyone heard of such a thing? I know that WPW can be asymptomatic and it seems paradoxical for someone with WPW to have bradycardia, so my first thought would be something outside of her diagnosed condition...She's, of course, talked it over with her cardiologist, but he didn't seem to be concerned.

Anyway, this is just for pure speculation and edification! I've told her to get a second opinion if she is truly concerned... The frustrating thing for me is that when I google this type of thing, nothing even remotely relevant seems to surface; or if it does I have to pay $50 to view it.

Thanks!

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[dphoenix]

I'm no cardiologist yet, but it sounds like she needs to see an EP specialist to figure out whats going on.

 

[rajgudi]

I came to know about a great Cardio pathologist in Chicago.., have your friend consult her or may be one of her staff. Her name is Dr. Saroja Bharathi.

 

[dragonfly99]

WPW...there are a range of phenotypes,
but I would be concerned w/the symptoms you are describing. Is she having documented bradycardia? Has she had one of those 24 or 48 hour Holter monitors (basically records a 24 hr continuous heart tracing, etc. for later analysis)? Perhaps consider a 2nd opinion from a cardiologist who specializes in arrhythmia.
I believe WPW can be associated with atrioventricular block, which could cause bradycardia.
We really don't have enough info to diagnose this online.
I would get a 2nd cardiologist opinion, and/or ask the 1st cardiologist to clarify why he doesn't think this is a problem.
If she is having syncope (passing out) I would get another medical evaluation ASAP, since that is not to be messed with in a WPW patient.

 

[mrantarctica]

what medications is she on? Amiodarone by any chance? Amiodarone causes bradycardia and hypotension in a LOT of people. and it's pretty much the most widely used anti-arrhythmic agent for all sorts of arrhythmias. many other anti-arrhythmics also cause bradycardia, but amiodarone is the usual suspect.

AV block MAY cause bradycardia in WPW syndrome, but only if the accessory pathway (bundle of kent) is unable to conduct impulses in an antegrade direction. In this mechanism - NONE of the sinoatrial impulses reach the ventricles, and a slow ventricular or junctional escape rhythm is responsible for bradycardia.

However, if the accessory pathway can conduct in antegrade direction - then it's virtually impossible for AV block to cause bradycardia.

Chances are your friend is either not measuring their pulse correctly, or there is some secondary cause of bradycardia - most likely due to some medications, or being a young fit person! sinoatrial disease doesnt seem to be associated with WPW as far as I know.

In any case - tachycardia is the worrying feature of WPW. bradycardia in WPW is possibly better - so long as they're not symptomatic.

The questions (with any arrythmia) to ask are
1) compromised or not? i.e. do they have symptoms of low cardiac output? if so, then they are compromised. in this setting they should be seen by a doctor in a medical institution with the facilities to deliver appropriate care.

 

[david713]

I have 22 years in private pracitce and 6.5 in academics. Your friend could very well have WPW and have bradycardia. The WPW is simply a short circuit in the conduction system. Tachycardia is produced when the atrial stimulus conducts over the aberrant pathway rather than the usual conduction system. The aberrant path is faster and re-entry occurs into the normal conduction system resulting in circus movement of the electrial potential and increasing accleration of the ventricular rate. Other arrhythmia such as atrial fib can greatly complicate the situation. Treatment is abalation of the offending pathway. Drugs are generally ineffective as they only work on the His bundle and may actually increase the potential in the aberratnt path. In atrial fib., only procainamide is the drug of choise as it increases the aberrant path action potential and thus reduces the rate of passage of the impulse. Other antiarrhythmics are not used.

Now simply because you have WPW does not mean you are using the aberrant path. It may only express itself occasionally or never. All that would be present would be a delta wave on the resting EKG. You friend's rate being low could be a matter of physical conditioning. If she is well put together then she would have a very low resting rate. Bush has a rate of 50 at rest. If she has seen a cardiologist then he has ruled out conduction system abnormalities such as heart block. On the other hand, if you friend is on the heavy side, she could be having sleep apnea and this might be associated with a low rate. If so she needs help.

I short exercise and don't worry about it if a cardiologist has passed on the situation.

 

[mrantarctica]

I have 22 years in private pracitce and 6.5 in academics. Your friend could very well have WPW and have bradycardia. The WPW is simply a short circuit in the conduction system. Tachycardia is produced when the atrial stimulus conducts over the aberrant pathway rather than the usual conduction system. The aberrant path is faster and re-entry occurs into the normal conduction system resulting in circus movement of the electrial potential and increasing accleration of the ventricular rate. Other arrhythmia such as atrial fib can greatly complicate the situation. Treatment is abalation of the offending pathway. Drugs are generally ineffective as they only work on the His bundle and may actually increase the potential in the aberratnt path. In atrial fib., only procainamide is the drug of choise as it increases the aberrant path action potential and thus reduces the rate of passage of the impulse. Other antiarrhythmics are not used.

Now simply because you have WPW does not mean you are using the aberrant path. It may only express itself occasionally or never. All that would be present would be a delta wave on the resting EKG. You friend's rate being low could be a matter of physical conditioning. If she is well put together then she would have a very low resting rate. Bush has a rate of 50 at rest. If she has seen a cardiologist then he has ruled out conduction system abnormalities such as heart block. On the other hand, if you friend is on the heavy side, she could be having sleep apnea and this might be associated with a low rate. If so she needs help.

I short exercise and don't worry about it if a cardiologist has passed on the situation.

Good advice. I didn't consider sleep apnoea at all actually.

Just as an academic point. The pathway of tachycardia you describe is known as anti-dromic tachycardia, and is by far and away the rarer form of tachycardia generation in the Wolff Parkinson White syndrome. More commonly, the AV node conducts sinoatrial impulses normally, which then utilise the Purkinje system and eventually activate the Bundle of Kent in a retrograde manner, causing circus electrical movement and re-entry tachycardia. This is the so called Orthodromic Tachycardia in WPW.

 

[shaolinRX]

Thank you for the excellent advice! Although some time has passed since my original post I'm certain she'll appreciate the information. I'll ask her a few of your questions if anyone is curious to delve further into the case.