effects of drugs on Sick Sinus Syndrome

[lots]

I have read the question and comments about the need
for a pacemaker on

   http://www.medhelp.org/perl6/cardio/messages/35404.html

(title - Sick Sinus Syndrome...ALWAYS a pacemaker?)

  I am in the same situation as "Duffer1" - 64 year old
female, usual daytime bpm around 48, but goes up into the
70s after exercise.  I have had a Holter twice, and both
times it showed bpm as low as 30 during the night, with
a few pauses of 3 secs., and one of 6 secs.  I have NO
symptoms during the day and am very active.  Cardiologist
says I will pass out during the day if I don't get a
pacemaker.

  The doctor's answer to Duffer1 referred to

  http://www.acc.org/clinical/guidelines/april98/dirindex.htm

as a source of guidelines as to which persons might benefit
from particular treatments.  This web page is no longer
available.  The doctor's answer said " In some patients, bradycardia is iatrogenic and will occur as a consequence of essential long-term drug therapy of a type and dosage for which there are no acceptable alternatives."

  I assume these drugs were listed in the article, which is no
longer accessible.

  PLEASE - can you tell me which drugs these are?  Maybe they
are beta-blockers, but I am not taking one of those.  But
I want to know what other drugs can cause bradycardia after
long-term use.

   Thank you.
                lots

[CCF-M.D.-MJM]

Hi lots,

The typical medications are beta blockers, some calcium channel blockers like verapamil and diltiazem, digoxin, and clonidine.  Stopping these drugs will cease there effect -- they are not permenant.

You have two possible indications for a pacemaker :

1. pauses >3.0 seconds (although usually means during waking hours, not during sleep)
2. chronotropic incompetence ( your heart rate doesn't go up as much as it should during exercise)

Maximum heart rate is determined by

220-age = x

220-64= 156 bpm

You may feel better with a pacemaker helping your heart rate increase.  It is very likely to improve your quality of life.  It is your decision though -- if you really don't want a pacemaker, you don't have to have one.

The link to the guidelines is not available for now.  I tried as well.  It should be back up soon.

I hope this answers your questions.  Good luck and thanks for posting.

[lots]

Thanks, Dr. CCF, for replying.  But none of the drugs you mentioned
was the one I thought you might mention - lithium.   I have taken
lithium for 33 years.  Go to
  http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed
and type   lithium sick sinus syndrome   in the search box, and it
comes up with 23 references.

Unfortunately, it is very expensive to request single copies of
these articles.  However the titles alone give you the idea.  And
I do not think they all refer to toxic doses of lithium.  One of
them refers to hypothyroidism, a common consequence of therapeutic
doses of lithium.

Does anyone else out there know anything about the possible
relationship between sick sinus syndrome and lithium?

I was very surprised to read your comments about the
pacemaker not being necessary.  Two cardiologists, my
primary physician, and a biomedical engineer friend of mine
who has had much experience in designing pacemakers,
have all said that if I don't get one, I will start passing out
during the day, because SSS only gets worse.

         lots

[appu235]

A related discussion, iatrogenic hypothyroidism was started.

[cavity]

A related discussion, Progesterone in sick sinus syndrome was started.