WPW vs. concealed accessory pathway

[hankstar]

Dear Doctor.

      Thanks again for taking my questions as i'm still a bit confused regarding well defined WPW , such as delta wave, a short PR interval and attacks of PSVT vs. a concealed accessory pathway.
      It is my understanding that WPW usually conducts antegrade from atria to ventricles, but can conduct retrograde also, ventricles to atria, usually triggered by PACs that can occasionally result in a-fib and conduct 1:1 to ventricle resulting in an extremely rapid ventricular response and even though rare can result in v-fib and sudden death.
     It is my understanding that a concealed pathway is only capable of  conducting retrograde( ventricle to atria) and the rate is usually slower, but retrograde rates can be excedingly fast also, a PVC usually initiates this PSVT from my understanding and most ECG shows no evidence of this and is completely normal. Am i right in assuming that risk of sudden death is much lower in a concealed accessory pathway than with well defined WPW, as there is no ventricular preexcitation in a concealed accessory pathway or is the lack of ventricular preexcitation only lacking on the ECG and is confirmed by an EP study or is there no preexcitation of the ventricles at all?
  It is also interesting to note that in most EP studies as rule when looking for SVT, you start the study with the ventricles and when looking for VT , you start the study with the atria, one might have assumed it was the other way around. Am I right or wrong? I just want to make sure I understand this.

   Thanks
         Hank.

[CCF-M.D.-RCJ]

Dr Matthews' site is great -- he has provided a great service to the public with his work.

In this one area, the explanation is not entirely accurate.  Some concealed tracts can certainly conduct in either direction (orthodromic or antidromic).

This one finding should not detract from the perceived quality of Dr Matthews' superb website.

[mightymuppet]

Hank, I found my old question i asked the doctor here almost a year ago..After a pac or pvc my heart done similar things to what you posted(although my heart raced for a shorter amount of time than you say yours did)..http://www.medhelp.org/perl6/cardio/messages/34011a.html

The racing after a pac or pvc was certainly similar and was a very uncomfortable experiance..Strange that such a small dose of beta blocker(i still take it)stopped it totaly for me..I'm still not sure what it was but i agree with what the doctor said in my question.

[medking]

Hank do you know anything with regards to what is deemed alot of PVC frequency and what is deemed low? I typically get a few hundred occuring during an episode that usually happens every 3-4 months and during a typical week, I may get none to several isolated skips per day ie. less than 6.  Also, although, all my tests are normal- echos, stress, cholesteral (high normal), bp normal etc ... I am wondering whether taking a dose of atenenol when these isolated ones begin is meaningful?  What is your experience with PVC frequency ? What is considered alot? And when does one get concerned.  I had one isolated situation last yr out of the blue when I had one skip that caused what I think 4-5 skipped beats in a row and then coughed and went back to normal? Never had this before...

[CCF-M.D.-RCJ]

Hank,

I would daresay that a good many cardiologists are also confused about WPW!

Concealed pathways are not, as a rule, just able to conduct in a retrograde fashion.  Whether or not a pathway is concealed depends on whether (1) signals first get through the AV node or not, and (2) the location of the pathway.  If a concealed pathway is slower than the AV node, then it will be concealed.  If a pathway is septal, and thus near the AV node, it will be concealed.

The bottom line for you is that the risk of sudden death is not well-studied in "concealed" vs "apparent"(WPW) pathways, but there is no real evidence to suggest that the risk of sudden death is different for the two types of paths.  It should further be stated that the risk of sudden death is very low with both types of paths.

Concealed pathways usually do lead to ventricular activation, just none that is seen on the EKG.

Your understanding regarding EP studies is correct, although this is more of a cultural decision, not evidence-based.

Hope that clarifies.

[dee gee]

I am new to this website and am curious as to "who is hankstar?"
You seem very knowledgable, but who are you?

[I'mallheart]

hey me again...ialso been especially the last few days having trouble breathing..lke shortness of breath and feel throat clugging up or something..my Mom says uts probaly stress and anxiety..i was at the mall toaday walking and was out of breath..this happend a few yrs back a month after being diagnossed with Pneumonia...they gave me a inhaler and the breathing machine they do for astma folks..what di u think//it comes and goes..
dave

[noreaster]

Hi. I've been reading your comments for quite a while and I'd like to say that I'm very impressed by your knowledge on cardiac issues.
This is not exactly on the topic but you've mentioned that you know how to read EKG. I was wondering if you would mind answering an EKG question that I have.
I had an EKG some time ago and it said that it shows signs of left ventricular overload. My cardio said that to him it looked OK. I'm sure he was right but I'd like to know what could have caused this difference in opinions.

[jkf]

Hi there,

I just wanted to let you know that I can totally relate to the fast rate with pvc's.  I get this about once or twice a year.  This always start with a very strange skip.  The pause is much longer than the normal pause between pvc's.  I mean it is at least 3-4 seconds.  Then, boom..my heart rate races and it is completely out of sync.  The last time this happened my rate was 220 with early beats all over the place.  Talk about an irregular heartbeat.  I honestly don't know how I was conscious.  And the wierd think was, except for the sheer panic of wondering how I was not unconscious, I really felt okay.  Usually this last about 3-4 minutes.  I just take 1/2 of a Tenormin and it settles.  This last time however, it went on for 15 minutes.  Is this what you are talking about?  Do you get this?

[noreaster]

Thanks. I

[medking]

Can eating a spicy food cause PVC's to start occuring? I just had some soup that has given me heart burn and these damn skips are here? Any insight is most appreciated...damn I hate these skips!!!!!!!!!

[medking]

Do you know whether its safe to take 12,5 mg of atenenol only for isolated occurrences of PVC's. My doc says its ok but I often wonder. I know the dosage is very low.

[medking]

Thanks alot ... can heartburn trigger the PVC's too? Or spicy foods?

[medking]

Hi Hank its Medking, just want to say, wow, really impressed. I thought I was knowledgeable about cardiac issues but I have a long way to go. Although my cardio says I should stick to Investment Banking and let him stick to cardio. In any case, I have a question, what do you know about taking atenenol is isolated circumstances ? I take 12.5 mg of atenenol only when I need it usually when I get excited mainly driven by anxiety induced tachycardia (sinus tach) then degenerates into PVC's arriving. That scares me and then I take a tablet of atenenol and it usually always works - no more PVC and tachy comes down to normal.  Also is it normal to get sinus tach from a PVC ? I had a situation where I had a PVC and the next thing I knew I was at 160 bpm in an ambulance freaking out. Is this normal ? Normal in so far that it is expected? Also, what kind of sustained pulse is required to produce cardiomyopathy or cardiomegaly ? Over how long a period ?  Finally, I often get nervous excercising when my pulse goes up high which often triggers the odd PVC which scares me even more, how do u handle this? When I am not nervous and have high pulse I never get PVC's ... kindly comment and thanks, Doc any insights ?

[michi]

hi hank,

just a short question for you!
what is your opinion about stress related tachycardia?
and sometimes a flip flop here and there. the atenolol 12.5 mg. helps a lot and i try to get off the beta blocker by april. i did cut it to 12.5mg about 3 weeks ago because my bp went a little more down than usally. 72/48  my normal one is 90/55 and i felt more tired. wonder why right? i know beta blocker do that so i was not too concerned.

michi

[I'mallheart]

thanks...so if i got off the atenolol and had more anxiety related tachy.. it could devolop into something worse..what is the cardiomypathy.. i will be okay right..
thanks
Dave

[I'mallheart]

just wanted to say one your one smart man..WOW...also thanks for all the info youve given me...i got my cardio report, inwhich ive never seen..i got it because i have new insurance and switching clinics etc. it states this is back on OCT 29 2003...After i had the event monitor and holter and echo..hes classified it as palps and anxiety...that is understandable..but at the bottom it says this, i dont know what they mean."I would, however, continue the small dose of atenolol 25mg on him at this point in time, a he is tolerating it very well, and atenolol obiviously will check his anxiety-related heart rate to go into a danger zone over a long period of time, as there is a nonenitity called tachycardia-induced cardiomyopathy.

what does that mean...i am not suppose to take it any more...
thanks
DAve

[I'mallheart]

when is it clear to stop taking atenolol..ive been on it for 6 mos 25 mg a day for anxiety related heart rate increase they say..did the tests just said palps and anxiety...is it okay to keep on atenolol? even if i may not need it unless it happens again where heart rate goes up..i just dont wanna be on it for no real reason and in the long run its doing more damage then good..thanks
cause sometime my bp is 99/58..pulse 50...and cold feet and hands..and sometime hard to stay errect
i am only 27