From:
Shelley Knudsen
Date: 2001-10-30 11:37:00 UTC
Subject: 3rd degree AV block reversal (long)
Hello,
Some of you may remember, I posted a month or so ago regarding
my ferret Taz, who was diagnosed with 3rd degree AV block on
top of his insulinoma. As of Sunday, and confirmed by ECG on
Monday, his AV block has disappeared. I am curious as to what
could have caused it initially, and what could have caused the
disappearance of it, and I would welcome any thoughts or
ideas.
Taz is a 5 1/2 year old male neutered sable ferret that I have
owned since he was 1 year old. He has always been very full
of personality, my primary troublemaker (and when you run a
shelter for 3 1/2 years, and own 20 some ferrets personally
over 10 years, that means a lot), and a very needy ferret when
it comes to attention. In December of 2000, Taz had his left
adrenal removed by my hometown vet, who is very good, and who
treated all of my shelter ferrets, but the only sterile part
of the surgery room is the instruments, the cover sheet, and
the gloves. Otherwise, no gown or mask, and people frequently
come in to ask questions, and the door is usually open to the
rest of the clinic. However, I've never had a problem with
the many surgeries that have been performed on ferrets of mine
there. I do not usually give an antibiotic post surgery, and
have never had a problem with that. Also, during surgery Taz
was on a heart monitor, and his heartbeat was normal.
In July, Taz started to shake more than the normal waking up
and excitement shaking. After many attempts, I was finally
able to obtain enough of a blood sample to do a glucose test
at home (with a very active ferret, and no help from my
husband who is "challenged" when it comes to any kind of
medical care for ferrets), and obtained 52, at which time I
started him on .5mg of pediapred once a day from some that I
had left over from other ferrets. When school started, I
brought Taz down here to Kansas with me. As I began to run
out of the pediapred, I made an appointment to take him into
the clinic here at school so that I could get a prescription
locally for some, and I began to taper down his dose so that I
would not run out before hand and have to cut him off for
several days. At the time, I knew you had to taper down to
discontinue pred, but I was not aware that if you discontinue
prednisone for an insulinomic ferret, their blood sugar will
crash lower than it was before. The night before and the
morning of his vet appointment, Taz had 2 major hypoglycemic
seizures, both of which I brought him out with first syrup,
then A/D, then the last of the pred that I had.
During his routine physical, (in early September) it was noted
that Taz's heart rate was only about 72, with a slight
abnormal sound that none of us could pinpoint. An ECG was
done ( a week later, to avoid undue stress), which revealed
3rd degree AV node block, which was confirmed by
echocardiogram (ultrasound). After a lot of research on both
my part and the exotic vet that was treating Taz (who is on
this list :-), it looked like a pacemaker was his only hope.
I contaced Dr. Kemmerer who was very helpful, and offered to
perform the surgery in Florida. However in spite of the
generous donation of a pacemaker, cost of the surgery and
transportation was an issue, so it was put off while I tried
to raise money for it. During the next several weeks, Taz's
insulinoma deteriorated, to where he finally seemed to
stabilize at 3mg per day. Also, in my research in the area of
human medicine and complete heart block, I came across a few
articles where AV node block had been caused by bacterial
infections, and parasites. I didn't really consider
parasites, but I did consider the bacterial infection idea,
especially because of his surgery in December. So, he was put
on .5cc of Clavumox per day.
A week ago, on Monday night, Taz had another severe
hypoglycemic seizure. What caused it, I have absolutely no
idea. All of his other symptoms from the insulinoma seemed to
be doing okay with the 3mg of pred. Also, earlier that night,
when I was listening to his heart, I noticed an occasional
extra beat. On Wednesday night (of course, the night before a
big test), Taz had what I can only call an episode. I was
giving him his eveing dose of pred, when his body suddenly
gave a jerk, and he started making raspy breathing sounds that
I have only ever heard before in ferrets that are breathing
their last breaths as they die in my arms. I tried to get a
pain stimulus, and was unsuccessful. Taz then went completely
limp (absolutely no muscle tone), his nose went completely
white, I saw no evidence of breathing (and I did look), and I
could not feel a heartbeat. The vet treating him thinks it
may have been a syncopal episode (fainting), which is
possible, I did not take the time to grab my stethoscope and
listen. Instead, I just went off of what I observed, and
initiated CPR. I had probably done about 20-30 compressions,
and about 4-5 breaths, when Taz began intermittent raggedy
breaths again, and as the breaths slowly increased in
frequency, to where it was finally very rapid shallow
breathing, his nose turned pink again, and he regained some
muscle tone, although he was still out of it. I again tried
to get a pain response, and he eventually did come around,
although when he did, he went right into a hypoglycemic
seizure. He eventually came out of that with A/D and pred
again, and when I listened to his heart with a stethoscope, it
was extremely erratic.
On Thursday, Taz seemed about average. However, when I
listened to his heart on Thursday over lunch, it was cycling
about every minute or so between double beats of about 136
bpm, and his more usual 70 bpm. It was the same on Friday,
although maybe a little more of the double beats. I do know
just enough about cardiology to know that an irregular
heartbeat is even worse than a very slow steady heartbeat, so
I scrambled to try and get him into a pacemaker surgery here,
as one of the surgeons here had indicated an interest in
trying it, we just had to get all of the specifics. I did not
listen to his heart on Saturday. On Sunday, when I listened
to his heart with a stethoscope, it sounded like a normal
heartbeat, averaging about 175-200 bpm.
Yesterday, Taz had an ECG, which revealed no evidence of 3rd
degree AV node block, just high QRS waves, indicative of
enlarged ventricles, which I already knew he had as a result
of compensating for the AV block. From what I have read in
human literature, 3rd degree AV node block does not typically
just correct itself on its own. Usually, once the AV node is
blocked, it is irreversible. So, my current questions for any
of the veterinarians or anyone with experience with human or
animal AV node block are these? Could it have been the
antibiotic, which he was on for 2 weeks, but which I
discontinued last Wednesday night when he had his "episode"?
Could the prednisone have done something? Could the cardiac
compressions have done it? Another thought by one of the
other vets here is that it could be lymphoma, and that it is
moving, and that it could reoccur, what is the chance of that?
Should he be going on any medications? One of the internists
here suggested two drugs, I think one was Theophyline, and I
don't remember what the other one was, but I'm not sure for
what, I didn't speak to him directly. Should I be treating
his enlarged ventricles, and if so, with what? To give some
kind of indication how much his heart had compensated, when he
had his ultrasound, his fractional shortening was 40, whereas
normal is 42, but his left ventricular end systolic was like
0.63, instead of the normal 6.4.
It seems to me (althought it could be my imagination), that
since about Saturday, Taz is slightly more active, is eating
more, and up for longer periods of time. However, I have
noticed an occasional spasm, minor, but it affects his whole
body.
I would really like to hear from anyone who has any kind of
input on this, not only for Taz's future, but also since I am
a vet student and a ferret nut at the same time, for my own
curiosity and learning.
Thank you,
Shelley Knudsen
Class of 2004 KSU Veterinary College
ferrets@kansas.net sknudsen@vet.ksu.edu
http://www.tcgcs.com/~ferrets
785-565-9041 cel402-984-4217
"There ain't no limit in this life to how far you can get,
but if you're going all the way, you gotta break a sweat."
- Chad Brock