From: Neal Lippman <nl@alum.mit.edu>
Newsgroups: sci.med.cardiology
Subject: Re: Heart Rate Too low? help?
Date: Wed, 13 Jan 1999 02:09:35 GMT

The proposed pathogenesis of neurally mediated syncope, or neurocardiogenic
syncope, is (in abbreviated form) as follows:
    A trigger, such as prolonged standing, leads to venous pooling,
presumably in the lower extremities, but perhaps in the splanchnic
circulation as well. [It is not clear to me how such triggers as blood draws
cause this to happen, btw].
    Said venous pooling decreases venous return to the heart, reducing
preload.
    The decreased venous return to the heart results in a decrease in cardiac
output, and a small drop in blood pressure. Note that thus far this is all
normal for assuming an upright posture.
    The heart receives a signal from the brain, triggered by receptors in the
aortic arch and carotid arteries that have informed the brain that the BP has
fallen. THis signal causes the heart to contract more vigorously (increased
contractility) to counteract the fall in BP.
    THe heart contracts more strongly; this triggers mechanoreceptors located
in the posterior wall of the LV, which feedback to the brain. Unfortunately,
these mechanoreceptors are more sensitive when the heart is underfilled (I am
not convinced that the animal data, used to support this argument, actually
shows what is claimed).
    Anyway, the mechanoreceptor feedback to the brain is inappropriately too
high due to the unloaded ventricle, and the brain gets the signal to deal
with this too vigorous cardiac contraction, to which it responds by a)
causing vasodilation by withdrawing sympathetic tone, b) slow the heart rate
by increasing vagal (parasympathetic) tone, or c) both.
    This results in a fall in the BP with loss of consciousness.
    Assuming the supine position increases venous return to the heart, and
reverses the process.

The theory is the beta blockers blunt the increase in cardiac contractility,
thus preventing that step of the process and blunting the reflex. In
practice, they work very well regardless of whether the theory is correct or
not.

Other drugs are often used, including as mentioned theophylline or
disopyramide. IMHO, theophylline is a minimally effective agent, if at all.
In the only randomized trial of disopyramide I am aware of, placebo was
actually more effective than the active drug.There are a lot of things which
are unknown at this point about this process.

Terri wrote:

> Joel Ureta wrote:
>
> > I'm 40 year old male, past marathon runner and triathlete with a very
> > low heart rate.  My cardiologist now has me on Pindolol (Beta Blockers)
> > to treat my condition.  Failed the tilt test miserably.
>
> Another question about this problem. Why are beta blockers used to treat
> people who "fail" the tilt test. It seems to me that a person whose
> autonomic nervous system is already not functioning properly with regards
> to heart rate and blood pressure, hardly needs a drug which will prevent
> the heart from speeding up in response to low blood pressure. What am I
> missing in this puzzle?
>
> Terri
>
> > My questions
> > are: What are Beta Blockers and what is there purpose.  I am not
> > training as hard as I use to but am working out just to stay in shape
> > and will not be competeing anymore.  Is my training ,30-40 minutes of
> > ocean swimming 2-3 times per week and light jogging 40 minutes, 2-3
> > times per week counter productive to my medical condition and am I
> > working against what my medication is trying to accomplish? What is the
> > medical term for a condition wherby ones circulatory & respiratory
> > systems are in excellent condition, but the neuro signals are
> > dysfunctional.
> >
> > Thank you for your help in advance.
> > Joel

From: Neal Lippman <nl@alum.mit.edu>
Newsgroups: sci.med.cardiology
Subject: Re: Heart Rate Too low? help?
Date: Wed, 13 Jan 1999 04:47:51 GMT

Yes, there have been some case reports of the response during tilt table
testing dramatically worsening after therapy with beta blockers was
initiated; I have seen the same thing 1 or 2 times myself in my own
patients. I am not aware that there are any predictors of who will have
this worsening response; I don't believe that 1st degree AV block is a
risk factor for this.

Neal

Terri wrote:

> Neal Lippman wrote:
>
> > The theory is the beta blockers blunt the increase in cardiac contractility,
> > thus preventing that step of the process and blunting the reflex. In
> > practice, they work very well regardless of whether the theory is correct or
> > not.
>
> Thank you for your detailed response. Have you ever known beta-blockers
> to worsen the problem both by increasing the frequency of such episodes
> and by prolonging the recovery time from a minute or two to as long as
> 15 minutes? Would a coincidental diagnosis of 1st degree AV block (in a
> non-athlete) make any difference?
>
> Terri

From: Neal Lippman <nlippman@altavista.net>
Newsgroups: sci.med.cardiology
Subject: Re: Tilt Table Test Questions - Help
Date: Thu, 07 Oct 1999 04:00:20 GMT

<FLAME>It continues to amaze me that so many people post here with basic
questions about tests they are scheduled to have (or have already had) and
about which they appear to have received no information whatsoever. I
suggest the following:

1. Part of your doctor's job is to explain to you what (s)he is thinking,
and what tests are to be done, what treatment is to be offered, and why. If
you doctor cannot or will not do this, you need to find one who will.
2. Part of your job as a patient is to pay attention to your doctor, ask
questions, and think for yourself. Now, I do understand that it is
overwhelming to see a new doctor and hear a long and detailed description
of what tests you will need, and why, and what complications may occur.
THerefore, I suggest that if you are seeing a specialist for a
consultation, or anytime you are seeing your doctor if you need to do this,
then a) bring paper and pencil and take notes so you can review them later;
b) bring along a friend or family member who can listen with you and to
whom you can talk later so that that individual can help you to remember
and understand when you are overwhelmed, c) write down questions beforehand
and take the list with you, so when you get flustered and cannot think of
what to ask, you have your list to help you, and d) if you get home and
realize that you didn't hear a word that the doctor said, call and let him
know that and ask for another appointment to go over things again. In this
regard, let me point out that if you have one or two quick questions, it is
perfectly reasonable to call and speak to the doctor on the phone to ask
them, but if you realize that you didn't hear a word that was said and need
the whole 30 minute discussion repeated, or if you want the doctor to
repeat this for your wife/husband/friend, you should understand that the
doctor is busy, his time is valuable too (actually, that's what we doctors
sell: our time/knowledge and our manual skills/procedures) and it isn't
fair to expect someone to spend a half hour on the phone repeating the
whole discussion again. Make an appointment. If my patients need that time,
I give it to them, but there's a limit to how much I can give away on the
phone.</FLAME>

Anyway, in terms of the tilt table test. THe point of the test is to
diagnose neurally-mediated syncope. Syncope means "passing out due to
inadequate blood flow to the brain." THere are a lot of causes for syncope,
and one is an abnormal brain-heart-blood vessel reflex that can lead to
inappropriate vasodilation (opening of the blood vessels) and inappropriate
heart rate slowing (either can occur alone or there can be a combination).
These effects occur at the wrong time, eg when the BP is normal or low
rather than elevated, resulting in a sudden fall in blood pressure and
syncope. This mechanism underlies common fainting spells, fainting during
blood draws, as well as some episodes of syncope that occur in other
setings such as coughing, passing urine, after prolonged stainding, etc.
Sometimes the "trigger" for an episode cannot be determined.

The tilt table test is performed by setting you up lying flat on a table
with ECG, BP monitoring (and sometimes other monitoring such as a catheter
placed in an artery to more accurately monitor blood pressure, or pulse
oximetry measurements). In special circumstances, other monitoring such as
transcranial doppler measurements of cerebral blood flow or an EEG are also
performed. After you are used to the equipment, you are tilted upright (you
are standing on your feet, not your head) for some period of time,
generally 30-40 minutes. Standing on the table, strapped in (loosely) to
prevent you from falling or moving around much (and in particular avoiding
moving your legs around excessively, which can affect the test results) are
crucial. The outcome of this test can be reproduction of a passing out or
near passing out spell, in conjunction with a fall in heart rate and/or
blood pressure. If such a response is not provoked, the tilt is often
repeated during or after administration of various medications including
isoproterenol, nitroglyerin, or adenosine.

Tilt table testing is very very safe, but of course complications care
occur. Fortunatley they are quite rare. For specifics that apply to your
situation, you really need to speak with your doctor.

Neal

Tom Tully wrote:

> Got no response from my last post so I thought I'd try again.
>
> I've had chest pain for years with lightheadedness, usually when
> exercising, but sometimes just from walking around and doing nothing!
> Panic attacks or anxiety diagnosis' rule the day, as of now. Last
> weekend I did a 7 mile hike that had produced still non stopping chest
> pain and dizziness! Hurts like hell! Doesn't sound like PA to me? So, I
> went to a cardiologist who saw a rather regular EKG (slightly short PA
> interval but nothing bad, even with chest pain).
>
> My Tilt Table Test is set for next Wednesday, followed by a stress echo
> on Thursday.
>
> The stress echo doesn't bother me. The tilt table, now that it was
> explained to me, does. How dangerous is this, given the fact that I
> still have chest pain after 3 days since I last exercised. Almost seems
> as if they stop your heart, or at least drop your BP pretty low. If
> disease does exist it would seem a somewhat dangerous test, No?
>
> Does anyone have any comments regarding this test. If so it would be
> greatly appreciated. Even bad stories are welcome. I like to be well
> informed!
>
> Thanks...
>
> Tom

From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.med,sci.med.pathology,sci.med.nursing,sci.med.pharmacy
Subject: Re: Need help interpreting brain CAT scan
Date: 3 Feb 2000 05:48:48 GMT

In <3897af34.7249829@news.wlg.ihug.co.nz>
kerryd@remove.this.bit.ihug.co.nz (Kerry) writes:
>>lying to sitting or standing.
>
>Does she have intermittent arrhythmias of her heart?

  The $64 question.  Of course, we don't know.  CTs and doppler carotid
studies of an elderly person with syncope merely serve to line some
radiologist's pockets.  And they have enough money already.



>Does she lose consciousness?  Does she just lose her balance?  Does
>she go white and pale?  Does she have palpitations?
>
>>
>>The most recent fainting spell was at the end of October. This
>>episode was markedly different from other ones.  Instead of just
>>outright fainting, she sat down suddenly because she felt weak.  She
>>then had a kind of "waking dream" where she thought she was helping
>>someone move furniture and called out for help.  This lasted 10-15
>>seconds, afterwards she was perfectly fine and there has not been a
>>repeat episode in 4 months.
>
>A TIA produces distinct neurological deficits, just like a stroke,
>that resolve and disappear within 24 hours.  Does she have
>cardiovascular disease?  Does she have any narrowing of her carotid
>arteries?  Has this been investigated?


   Yes, as you see.  Wasted money.  The only guy I've ever seen faint
multiple times from carotid disease was a truck driver who fainted
every time he looked over the right shoulder, but not the left.  He was
a smoker with 2 blocked basilar arteries and one blocked carotid.  He
was one of these minority of people (about 1 in 4) with perfect
communicating arteries in the circle of Willis.  He was running his
entire brain on one carotid.  When he turned his head hard, he kinked
that one.

   There is a lesson here.  It takes a seizure or global brain
metabolic shutdown to make you faint a number of times, and be just
fine shortly after.  It's damn difficult to have the carotids be the
cause of this.

From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.med,sci.med.pathology,sci.med.nursing,sci.med.pharmacy
Subject: Re: Need help interpreting brain CAT scan
Date: 3 Feb 2000 05:39:10 GMT

In <878aau$ke3$1@nnrp02.primenet.com> camilla@primenet.com (Camilla
Cracchiolo, R.N.) writes:

>An elderly person in my family has had several episodes of fainting
>over a period of four or five years.  We've never been able to
>pinpoint a cause. (more details and history follow the CAT scan
>report).
>
>The obvious question about her fainting is whether she is having
>TIAs or not. Her most recent CAT scan states the following:
>
>"The ventricles and cortical sulci are moderately to markedly
>enlarged consistent with atrophy and diffuse white matter disease.
>The paraventricular white matter disease extending superiorly in the
>corona radiata into the centrum semiovalae is nodular with the
>appearance of numerous lacunar infarcts.  There is also a suggestion
>of some ischemic changes in the brain stem.  There is no edema or
>mass effect.  Specifically, there is no evidence of mass in the
>right temporal lobe.  The visualized paranasal sinuses and orbits
>are normal."
>
>"Impression: Moderate to severe atrophy with extensive diffuse and
>nodular symmetrical periventricular white matter disease, most
>consistent with ischemic changes."
>
>QUESTIONS:
>
>Does this mean she's been having TIAs after all?


   TIAs almost never cause fainting. Doing a CT to look for the cause
of fainting in a person who has no neurological deficit afterwords is
is a huge waste of everybody's money.  Just one reason Medicare is
headed for disaster.  The lady may have had TIAs, but odds are very
good that they are not what is making her lose consciousness.



>Should she take some kind of anticoagulant like aspirin?
>
>Would this type of atrophy be expected to cause cognitive changes?
>(She's been slowing down a little lately, and repeats old stories,
>but she's oriented, memory for recent events is good and has nothing
>else that would suggest Alzheimer's or other dementia.)
>
>Her balance is bad.  Would that be due to this kind of change?

   Incoordination of the legs correlates quite often to periventricular
white matter disease from many small infarcts (tiny strokes, sometimes
without symptoms). Of course, balance is a hugely complicated thing,
involving many systems.  The problem is that CT is not very sensitive
and not very specific.  One can see this kind of thing, and cerebral
atrophy, in the elderly without any symptoms at all.

   In somebody with symptoms (leg problems), aspirin is a
consideration.  It won't stop the fainting, however.

   The history below, which includes a prodrome while sitting, would
suggest a heart arrhythmia resulting in low blood pressure, such as
intermittant atrial fibrillation or heart block.  If this is rare it
may be missed on Holter, and you'll know nothing unless the monitor is
going *through* an episode.  I would suggest you think about an event
marker type cardiac monitor which can be used for several weeks.  It
records EKG on a continuous loop, which can be stopped to review the
last minutes to hours, whenever someone faints or feels dizzy.  If they
don't have any symptoms while wearing it, it's also therapeutic <g>.
You win either way.




>HISTORY:
>
>She has had three episodes of fainting. Episodes of fainting
>previous to the most recent one involved her feeling dizzy and then
>waking up on the ground looking up at a bunch of concerned faces.
>One episode happened while standing in line for a long time.  This
>caused the doctor to suggest it was vasodepressor syncope (she does
>have swollen ankles and venous stasis).  Another episode, however,
>occurred while she was sitting down.  She was at a homeless shelter
>passing out food, felt "funny", and told people she had to go home
>early.  She then got up, tried to walk to her car and keeled over a
>few feet away.  The episodes seem to last about 10-15 seconds.
>
>The most recent fainting spell was at the end of October. This
>episode was markedly different from other ones.  Instead of just
>outright fainting, she sat down suddenly because she felt weak.  She
>then had a kind of "waking dream" where she thought she was helping
>someone move furniture and called out for help.  This lasted 10-15
>seconds, afterwards she was perfectly fine and there has not been a
>repeat episode in 4 months.
>
>We previously thought her fainting might be due to medication, since
>she's been on anti-cholinergics for a bladder problem.  At the time
>of the first two episodes, she was on ditropan.  The dizziness
>stopped when she discontinued the ditropan and had no further
>episodes for about a year.  The most recent - and different -
>episode occurred after she began taking imipramine for the same
>bladder problem. She has had no repeat episodes since discontinuing
>the imipramine; however, she's only been off it for a couple of
>months.
>
>
>Physical findings:
>
>Carotid doppler is normal.  Holter and regular EKG are normal except
>for left bundle branch block of long standing. No arrthymias,
>murmurs or obvious cardiac abnormalities. No other neuro signs. EEG
>is normal.
>
>
>MEDICATIONS:
>
>She takes levothyroxin for hypothyroidism, was a little hypothyroid
>recently but the dosage was changed and she was euthyroid at the
>time this fainting episode occurred.  Has recently discontinued HRT.
>Takes ibuprofen for arthritis.  She also takes a variety of
>antioxidant vitamins for macular degeneration and the herb bilberry.
> (There's not a whole lot of research on bilberry, but it decreases
>vascular permeability, suggesting that, if it has any effect at all,
>it would counteract venous stasis.)
>
>OTHER RELEVANT HISTORY:
>
>She is 74 years old.
>
>She just underwent radical hysterectomy and lymph node sampling for
>endometrial cancer (last week, actually). We were concerned about
>the possibility of a brain metastasis, but there doesn't seem to be
>anything to support that theory.   In addition to the CAT scan
>stating there was no mass, the path report states that the cancer
>was Stage I, grade 2.  The tumor was smaller than 3 mm and was less
>than one sixth of the way into the myometrium, with no involvement
>of the lower uterine segment.  Lymph nodes are clean.
>
>She survived septic shock from cellulitis in 1994, had a bout of
>sepsis from a UTI in 1998 (did NOT lead to shock, fortunately).  Has
>frequent UTIs.  She has slight osteoporosis on chest X-ray, for
>which the doctor has recommended increased calcium intake since she
>can no longer take estrogen.
>
>I'm open to comments and ideas.
>
>Please send me an e-mail copy of any replies you post to the
>newsgroup.
>
>Thanks.
>
>
>
>-------------------------------------------------------------
>"The trick is to keep an open mind, without it being so open
>                   that your brain falls out"
>
>                    Camilla Cracchiolo
>                     Registered Nurse
>                  Los Angeles, California
>                          USA
>
>camilla@primenet.com         http://www.primenet.com/~camilla
>
>

From: David Rind <drind@caregroup.harvard.edu>
Newsgroups: sci.med
Subject: Re: Weird medical question
Date: Thu, 09 Sep 2004 21:24:07 -0400
Message-ID: <chqvnv$srj$1@reader1.panix.com>

TJ Poseno wrote:
> Today in my Auto Tech class the instructor was showing a video of a
> Eye operation (Disgusting) to show the reason to wear safety glasses
> all the time.
>
> Anyway, one of the kids "passed out" like fell on the ground out cold.
> They picked him up and he got all tense (still out pretty much) and
> held his arms close to his body (kinda liek if your mimicking a
> chicken but with your arms clsoe to you) and started shaking. First
> response was to say it was a seisure.
>
> That only happened for no more than 7 seconds then his eyes opened and
> he was way out there, as in he had no idea what happened and looked
> VERY confused.
>
> They made us leave and he went to the hospital I assume.
>
> Just out of curiosity does anyone know what it could of been? Im very
> curious. Im almost sure this wasnt triggered by the gross ass video,
> but peopelpass out with stuff like that and wonder if that could have
> been a factor.
>
> Really curious about this.

This is pretty common. People who faint in a situation like this
(usually called "vasovagal syncope" or "neurocardiogenic syncope") will
often have some brief seizure-like movements if something prevents them
from lying flat (and thus deprives the brain of blood/oxygen) during the
faint. Generally speaking, no evaluation or treatment is required.
Nothing about this suggests that the person has epilepsy.

--
David Rind
drind@caregroup.harvard.edu

From: David Rind <drind@caregroup.harvard.edu>
Newsgroups: sci.med
Subject: Re: Weird medical question
Date: Fri, 10 Sep 2004 06:48:38 -0400
Message-ID: <chs0qd$93g$1@reader1.panix.com>

PF Riley wrote:
> On Thu, 09 Sep 2004 21:24:07 -0400, David Rind
> <drind@caregroup.harvard.edu> wrote:
>
>>This is pretty common. People who faint in a situation like this
>>(usually called "vasovagal syncope" or "neurocardiogenic syncope") will
>>often have some brief seizure-like movements if something prevents them
>>from lying flat (and thus deprives the brain of blood/oxygen) during the
>>faint. Generally speaking, no evaluation or treatment is required.
>>Nothing about this suggests that the person has epilepsy.
>
>
> This is most likely vasovagal syncope with an associated
> pseudoseizure.
>
> PF

Do you mean "pseudoseizure" in the way it is normally used? (That is, a
fake seizure under the voluntary control of the patient.) If so, I
disagree that this is what is seen with vasovagal syncope.

--
David Rind
drind@caregroup.harvard.edu

From: David Rind <drind@caregroup.harvard.edu>
Newsgroups: sci.med
Subject: Re: Weird medical question
Date: Sat, 11 Sep 2004 08:51:45 -0400
Message-ID: <chusda$8kf$1@reader1.panix.com>

PF Riley wrote:
> On Fri, 10 Sep 2004 06:48:38 -0400, David Rind
> <drind@caregroup.harvard.edu> wrote:
>
>
>>PF Riley wrote:
>>
>>>This is most likely vasovagal syncope with an associated
>>>pseudoseizure.
>>
>>Do you mean "pseudoseizure" in the way it is normally used? (That is, a
>>fake seizure under the voluntary control of the patient.) If so, I
>>disagree that this is what is seen with vasovagal syncope.
>
>
> No, I meant, in the broadest sense as would be implied by the term, a
> "nonepileptic episode that simulates an epileptic seizure." I would
> not claim to know whether the act was voluntary or not.
>
> I think it is unfortunate that a generic term such as "pseudoseizure"
> would to you mean immediately not only "fake" but "voluntary!"
>
> See:
>
> http://www.emedicine.com/neuro/topic403.htm
>
> "A generally accepted view is that most patients with PNES fall under
> the somatoform category rather than the malingering or factitious
> category."
>
> PF

PNES stands for "psychogenic nonepileptiform seizure" and you can
substitute that for "pseudoseizure" and I still don't believe that's
what happened.

Whether you think pseudoseizures imply faking/malingering or whether you
think they are somatoform events some of which are outside of voluntary
control (conversion reactions), neither one describes the seizure-like
activity seen after a vasovagal episode.

However, the initial definition you give above for a pseudoseizure
("nonepileptic episode that simulates an epileptic seizure") does
include what is seen after a vasovagal episode. It's just not the usual
meaning of pseudoseizure, which is why I wondered what you were saying.

Note again that the definition of PNES you posted would not include the
seizure activity seen after a vasovagal episode -- there is nothing
"psychogenic" about that seizure activity.

I don't think we actually disagree. I think you just used a term in a
nonstandard way. "Pseudoseizure" has a standard meaning that is not as
inclusive as the way you are choosing to define it. My brief definition
of pseudoseizure as being faked was somewhat narrow since it excluded
those people with conversion reactions and other somatoform disorders.

--
David Rind
drind@caregroup.harvard.edu