Confused about accessory pathways

[LilViking]

Hi everyone,

I'm having an EP study tomorrow to confirm that the episodes I'm experiencing every few months are, in fact, PSVTs, and to look for the cause. I assume that one thing the doctor will look for is an accessory pathway. However, I've had several ECGs after my episodes (never during, as I've never made it to the hospital while they are still going on--they only last a few minutes), and they looked completely normal. Are there accessory pathways that don't show up in an ECG? If so, how come accessory pathways are only active sporadically, and not all the time?

Thanks for your help!

[Artaud]

Hi,

I don't know about the accessory pathways (per se), but I have PSVT at times. Apparently you can have Reentrant PSVT or Accessory Pathway PSVT. While at the Cardiologist one day, trying to enhance my knowledge of my problems, I happened to mention to the Doctor that it was interesting how the signal loops around and reenters, resulting in another beat, and another loop, etc. He looked up and said "you don't have reentrant PSVT". He didn't say I has Accessory Pathway PSVT, but from looking at material online, it seems likely that I have the Accessory Pathway form.

The point in me conveying this is that I have never had anything but Holters, EKGs, and Loop Monitors (Event Monitors) that he would be able to view. To my awareness, it was only the Loop Monitor that captured the PSVT. So, by extrapolation, it seems as though he was able to determine, strictly by the results of the Loop Monitor, that I had Accessory Pathway PSVT and not Reentrant PSVT.

I would not imagine that the Pathways are evident all the time, and I am not sure if the EKG can determine the pathway even if it is occurring. I believe this is the reason for the EP Study. A careful and accurate mapping of the conduction system of the heart, with the disorder being evoked under  carefully controlled conditions.

Why are the pathways only sporadically active? Good question. Those of us with arrhythmias commonly have episodes when the arrhythmias are more severe and other times when the hardly exist at all. It would be nice if they always hardly existed as well.

Please sleep well tonight and be sure to get back to the group with your results.

Best of health.

[tickertock]

They are called Concealed accessory pathways because they are not manifest on the  EKG with the usual short PR , delta wave and widen QRS complex such as is the case with WPW syndrome , they are sometimes referred to as concealed WPW syndrome. The concealed pathways usually conduct retrograde from ventricle to atria which would be less likely to cause the rare occurence of extremely dangerous rates with atrial fibrillation that occurs with manifest WPW that is seen on EKG.Please note these occurences are extremely rare and almost on par with the normal population, ask your EP about it and see what he says. Good luck.