What makes PACs and SVT tick?

[anacyde]

They come, they go.  One month exercise causes them, the next month exercise is the only time they don't pester me.  For months I could predict ovulation to the DAY just by the palpitation pattern.  Now, there's no discernable pattern at all.

I'm a person who needs to know how things tick.  It's more curiosity than anxiety.  It's a drive, a need to know.  I took apart all my toys as a kid because I wasn't just content to play with something, I had to know the mechanics of it.  Why does the doll talk?  Why does the car go when you wind it backward and let go?  How do the wheels on this thing stay on it?  And this is exactly the same.  SOMETHING causes these PACs.  While we all know the traditional triggers, something is changing that makes us more prone to them.  WHAT!!?  A combination?  No, because I could have HALF the usual combination and I feel this way, or the entire puzzle and have no symptoms at all.

It seems a few of us developed atrial arrhythmias after having children.  Clearly, this isn't limited to people who have cardiovascular problems in pregnancy (PPCM, pre-eclampsia, etc.), in fact I think most of the women who develop palpitations afterward have otherwise very normal hearts.  So what is it about pregnancy that does it?  Hormones?  Cardiac structural changes?  Are there different states similar to pregnancy that bring about new PACs and SVTs for people?  Is it all in the hormones?  Is it autoimmune?  Is there an inflammatory process?  Is it somehow environmental?  I'd be interested in how it stacks up statistically too, for instance, how symptomatic are people in the northern US versus the southern US?  And east and west too, for that matter.  Does time of year make a difference?  And are all the things that "help" also just coincidences of timing?  It's enough to keep a researcher happily busy for a very long time.  

You know what I'd like?  I'd like enough money to go to medical school.  I'd go into cardiology/electrophysiology and would devote my career to searching for the answers to the questions that keep us up at night.  Sometimes I kick myself for not following my dream of becoming a cardiologist, something I wanted long before I ever knew what a palpitation felt like.

[Momto3]

Thanks!  Great question!!

[arthur]

The posting is entitled Blood Pressure and Arrhythmias (under the Rhythm forum).  The good doctor concurred that hypertension tends to increase PACs/Afib...and likely most other foci-related arrhythmias.  ACE inhbitors (and ARBs) are pretty specific in lowering BP by affecting the arterial wall tension through related mechanisms not much else.  Kind of nice to see a theory (not entirely my own) consistent with the facts.  -Arthur

[susabelle28]

I wonder if the use of ARB's could possibly have a beneficial effect on arrythmias as well?  The ACE's and the ARB's are similar, I think.  I'm currently trying avapro for my blood pressure and my internal medicine doc keeps saying how the ARB's are such a great class of drugs.

Susan

[Momto3]

Where is your question (to the doctor) regarding the use of ACE inhibitors and their effect on arrythmias?  I keep looking for the post, but haven't seen it.  I take lisinopril and am curious about its potential benefits for pvc recurrence.  Thanks!

connie

[arthur]

Sorry...I really don't know much about inappropriate sinus tach...My expertise focussed on AFib/PACs and has evolved because of a desire to learn as much as I can about my personal condition.  I don't think that the explanations are beyond the grasp of any normal human being. Unfortunately, many doctors are not very forthcoming with explanations, so you need to dig in yourself and ask the important questions, and seek help from other sources.  I wish you the best.  -Arthur

[sugarpea013]

Hey there, I am so impressed with your knowledge I must say! I was wondering if you happen to have any comments/suggestions/advice in regards to inappropriate sinus tachycardia? Thanks so much in advance.

[arthur]

I just posted a question to the MD about the use of ACE inhibitors and their potential effects on lowering the frequency of arrhythmias.  It will be interesting to see if the EP community is aware of any effect.  -Arthur

[anacyde]

That is very interesting Arthur.  I'd be interested in seeing if others have experienced similar relief while on ACE-I meds.

[arthur]

A further note...if one has a partially concealed abberant pathway, ie, a focus which is nearly isolated so that one gets a PAC/PVC or even Afib once in a while (under stress, high adrenaline, etc), AND one has a tendency toward high blood pressure (even if it just spikes, under stress for example), my EP suggested the use of a blood pressure medication to (1) obviously reduce the pressure and (2) not so obviously, reduce the chance of opening microchannels and eliciting an arrhythmia.  I haven't seen much discussion on the effects of blood pressure meds on PAC/PVC production (outside of beta blockers, where the effect is not too clear since BBs affect the arrhythmia as well as pressure).  Personally, I know I have a focus or two which can kick up lone AFib under stressful circumstances, and with the advice of my EP, I started taking low doses of an ACE inhibitor (I have slightly elevated blood pressure).  For the past year I've noted a sizable decrease in PACs and incidence of lone AFib.  So, with N=1, the cause/effect relationship for me appears to hold. It would be interesting to see if other folks with such concealed pathways have a similar experience with blood pressure meds.
-Arthur

[anacyde]

Your posts are a welcome and enjoyable addition to the forum conversations, and it seems many share my opinion.

What you mention of the extra cells in the heart also explains the heart's ability to heal from cardiomyopathy (as mine did) when the disease isn't terribly severe.  I've always wondered if, when healing, the cells that were called to action to pick up the slack were just a bit mor irritable or just adjusting to the change in how things operate in there.  Or as another poster mentioned, irritability caused just by the normal strains of pregnancy.  Any pregnant heart expands just a little due to increased blood volume (3mm or less, typically) and since the heart is a relatively small organ it stands to reason this could be enough.

And I often think of it in terms of muscle.  I have muscle spasms from time to time, where the muscle just gets irritable.  I doubt the heart is immune to such irritability.

I hope you'll post more, Arthur.  I enjoy people who think.  Something doesn't have to be perfect, exactly right or said by a doctor to be valuable.  Sometimes just discussion on hypotheses is really interesting and enlightening.

[finetilthree]

I'm glad to see all of you back and posting.  Reminds me of the good old days when I found this forum eighteen months ago!

[Momto3]

See Arthur, you really must come back : )

[deedle1976]

I always look out for your posts Arthur. I figured you were a scientist! I'm also a biologist (PhD in Molecular Genetics) so I'm very interested in the underlying mechanisms for arrhythmias and in what's potentially going on at the molecular level. I haven't done as much research as you though so your posts are always a great source of information.
Denise

[dolfnlvr]

Hmm.  Makes a bit of sense then.  So many women have stated that they "were fine until...." after a pregnancy, or multiple pregnancies.  The increased blood volume through the heart muscle during pregnancy could induce strain...not abnormal strain, but strain none-the-less.  And, once blood volume returns to normal levels I can see where microchannels may be "opened."  

Very interesting.  I'm going to read those posts.  Thanks again.

And, you're right Arthur.  Obviously selection has not kicked us out of the gene pool yet :-).  

[arthur]

Thanks for the kind comments.  The second post in Momto3's list is probably the most interesting as far as the mechanism for premature beats is concerned.  The entire scenario is consistent with modern medicine's understanding.  The question of "why now?" when "I was fine all these years" is tougher...the only glimpse of a reasonable hypothesis (once again, taken from an expert EP) is that with age (and/or tons of exercise) cardiac tissue may expand.  The result is that microchannels could develop with time (larger spaces between cells), which allow ions to pass through...bingo, a focus which was isolated before, now leaches some of its troublesome ions further out and possibly into a normal depolarization circuit.  One major comfort in all this research is the realization that all our hearts contain a number of foci (electrically active cardiac cells) embedded in areas of the cardiac muscle where they are not needed.  Blame Mother Nature.  So, this is not a disease...it's just the way things are.  A further comfort...if evolution is an active process in the development of mankind, it's clear that PACs and PVCs were not a strong enough factor in making a survival difference, since we've all evolved with them.  We've been millions of years in the making...maybe there's a survival ADVANTAGE in having them!

-Arthur

[Momto3]

Here are two posts that include some of Arthur's comments:

http://www.medhelp.org/forums/cardio/messages/32387.html
http://www.medhelp.org/posts/show/254765

If you search the Heart Forum, you are likely to come up with many others.

Arthur's own experiences with arrythmias and ablations coupled with his education and research have led to some great discussions.  The posts are definitely worth reading....

[dolfnlvr]

Please.  A PhD might be just the type we could most communicate with!!!  Medical Drs.  don't seem to, on a whole, care to delve too deeply into this topic, as it is not "fatal."  Understandably, there are other pressing issues to research, and I understand that, but with your background and research, perhaps you could shed a great deal of light on the subject for those of us who are extremely curious and hungry for readable, but pertinent information.

I'm going to look of former posts of yours.  But I'm fairly new here.  Can you give me some KEY WORDS to use in the search??

Thanks!!!

[finetilthree]

Yes, I agree too.  Arthur's posts always gave me peace of mind in dealing with my arrhythmias.  Please reconsider and continue to post.  If anyone finds the other posts he was speaking of, please post them again here for me to review.  Thanks!

[fearfactor]

I agree, Arthur's posts were very useful and informative.  Thanks for them.

[Momto3]

A lot of us look forward to your posts.  Your personal experiences and knowledge are gifts to the forum.  You are absolutely within your rights to post your opinions.  Don't let a few naysayers spoil it for the rest of us.  The vast amount of experience and information that can be exchanged here, is incredible.  Won't you please reconsider posting more often?

connie

[arthur]

These were posted within the past year, and I believe before the forums were segregated, in the "community" forum....If you have trouble located them, I'll be happy to provide a synopsis.  I stopped posting these bits because of the gross negative feedback received from others on the forum.  It would appear that some rather vocal types on the forum would prefer that my opinions be kept to myself, since I am not a medical doctor....I do have a PhD in biochemistry, and have spent the last 5 years or so digging up information from journal articles and discussions with cardiologists and researchers in the field of arrhythmias.  The opinion that I have expressed represents a synthesis of all these expert sources.  -Arthur

[anacyde]

Which of the heart forums?

[arthur]

Check the posts by Arthur...there is a reasonable understanding of the PAC/PVC phenomenon, and it has to do with the state of the autonomic nervous system which, in turn, affects the activity of isolated foci (normally occurring in cardiac muscle).  -a

[anacyde]

dolfnlvr: Agreed!  I do wonder if the doctors are confounded, or if they just take the more common arrythmias with a grain of salt since they've been proven benign.  Medically speaking, this is true.  However, as many will note, there is a large psychological component to this as well.  I think the toll it takes on some from a purely psychological standpoint affects quality of life enough to warrant further investigation.  And beyond that, well, it's just neat.  I enjoy meeting people who share my curiosity about things.  Some people think I'm spinning my wheels, making myself nervous, etc. but to be honest, researching and asking questions (in an active manner, seeking answers) is fun for me, enjoyable.  While the palpitations did make me nervous at times, my need to know isn't anxiety driven.  I think you "get" me :)

Momto3: Thanks!  I'm starting nursing school soon actually.  With two very young kids and graduating from college this semester, I see already how much just a small course load takes away from family time.  Being a doctor probably isn't workable right now (I had a friend who was in med school...the hours required, all they go through, it's rough).  My dream of dreams is to work in cardiology.  I know I would enjoy the job and the patients.  Between my palpitations and previously having PPCM, and my family full of CAD, I know what it's like to see through their perspective.  What I'd really love is to be a nurse somewhere like the Cleveland Clinic, where there is a huge center with cutting edge technology and innovations and research, and lots of different people, challenges and learning experiences.

ReelEscape: Wow...you've really been through it with the thyroid and a-fib.  They keep checking my thyroid since palpitations are a common symptom, but it always checks out perfectly.  Hopefully it stays so, I know what a bugger it can be.  You are right about stress, it's definitely a trigger.  My anxiety about the palpitations isn't so much a factor, but my desire to know what makes them tick is always at the forefront.