on the 24-hour monitor
van de Stadt, ex-FAB scholar at Langford, reports on a case she
saw there in 2000
A FOUR-and-a-half-yearold neutered male domestic shorthaired
cat, was referred to the Feline Centre in July 2000 because
he kept fainting. He was having several fainting episodes
a day, during which he collapsed and was flat out for about
four seconds. He then shook his head and immediately recovered.
tests showed no abnormalities and tests for feline immunodeficiency
virus (FIV) and feline leukaemia virus (FeLV) were negative.
ECG and blood pressure measurements also showed no abnormalities,
even when measured straight after a fainting episode. Radiographs
of the chest and abdomen showed nothing significant. However,
ultrasonography revealed that the ventricles of the heart
were not beating sometimes when they should have done. An
ECG trace made at the same time confirmed this. However, because
Tooye was under a general anaesthetic when he was ultrasounded
we were not sure whether this was the cause of his fainting
when he was awake!
asked the help of Langford's lecturer in cardiology, Dr Luca
Ferasin. We decided to try Tooye on an ECG monitor which would
record Tooye's heart activity constantly for 24 hours and
would hopefully be able to tell us whether Tooye's heart had
stopped beating and, if so, when it had happened. It was the
first time the monitor had been used for cats at Langford.
monitor consists of a tape recorder and ECG leads which are
connected to the animal. Dogs carry the tape recorder around
attached to their bodies, but it is too heavy for cats to
do the same. We decided to try and leave the tape recorder
in the kennel, attached to Tooye. The leads were covered with
tape, to prevent Tooye from biting through them and the electrodes
on his skin were covered with a bandage. Tooye was fantastic!
He coped very well with the machinery attached to him and
a perfect 24 hour tape was recorded. The tape was then sent
to Karen Langford at a hospital in Taunton where it was converted
into a proper ECG.
tape confirmed what we had been fearing. At some stages the
ECG trace showed no activity, indicating that the heart had
stopped beating for a short episode (frequent prolonged episodes
of complete atrioventricular block with ventricular standstill).
During such an episode the outflow of blood from the heart
to the rest of the body is minimal and the animal will faint.
No medication can do anything to prevent this and the risk
of sudden death in one of these episodes is significant.
only chance of cure would be to place a pacemaker in the heart.
When the heart stops beating the pacemaker notices and quickly
gives a little stimulus which makes the heart start beating
again. The pacemaker would start Tooye's heart going again,
preventing him from fainting. But where to get a cat pacemaker?
Karen Langford helped. She came to the Feline Centre with
a paediatric (child's) pacemaker and helped to programme it
while Mr Hotston Moore, Langford's lecturer in soft tissue
surgery, and Luca were performing the surgery. The pacemaker
itself was put in under the skin, just behind Tooye's elbow
and a lead went through one of the big heart vessels into
the heart. The tip of the lead sends information through to
which can respond when necessary by sending back a stimulus
to the heart and making it contract.
recovered from the surgery and coped well with his implanted
pacemaker. He was discharged and was reported to be doing
very well. No more episodes of fainting were seen by his owners
and Tooye was enjoying being outside in his beautiful garden.
Tooye did develop complications. A few months after surgery
his owners noticed that Tooye's breathing was becoming laboured.
Tooye returned to Langford where he was diagnosed with a chylothorax
(accumulation of lymphatic fluid in the chest) Chylothorax
is seen in people with pacemakers and is likely to be caused
by irritation by the pacemaker leads. Because of the volume
of fluid in the chest it is hard for the animals to breath
properly and they get very breathless (dyspnoeic). Sometimes
the fluid dries out by itself, but sometimes removal of the
cause (in this case the pacemaker) is necessary. The fluid
was drained and Tooye immediately breathed much more easily.
However the fluid built up again over the next few weeks and
required further drainage. The fluid came back after each
drainage, despite several courses of medication with drugs
used in people with the same complication. Removal of the
pacemaker could possibly stop the fluid but would cause the
fainting again, with all its risks. It was a very difficult
needed his chest drained more and more frequently and started
to lose his appetite, raising the question whether it was
right to continue treatment. His owners felt that Tooye's
quality of life was deteriorating and decided that he should
be put to sleep as there were concerns that more surgery to
remove the pacemaker, although removing the fluid accumulation
problem, would not cure his heart problem. He was put to sleep
five-and-a-half months after the pacemaker was implanted.
this is sad ending, it was a case from which we all learned
so much and hope to be able to use the information in the
future to benefit other cats. I would like to thank the referring
vets and would like to dedicate this article to brave Tooye
and his lovely and understanding owners.