Staying in Pace with Pacemakers
Posted February 02, 2012
What would you do if your pet's heart suddenly stopped working
properly? February is the month of National Heart Awareness and
Valentine's Day. February should also be a reminder for pet owners
to educate themselves on their pet's heart health. The best place
to start is your veterinarian.
If your pet has an irregular heartbeat or low heart rate it
should be evaluated by your veterinarian and may indicate the need
for a pacemaker.
"Pet owners are often amazed that their pets can live for years
and feel much better than they have in a long time after receiving
a pacemaker," says Dr. Ashley Saunders, assistant professor at the
Texas A&M College of Veterinary Medicine & Biomedical
Sciences (CVM). "Even younger working dogs that assist in
border patrol and drug sniffing are able to perform their duties
the same way a normal dog would after receiving a pacemaker."
Dogs with low heart rates tend to move slower and are likely to
tire more quickly, because blood is not being efficiently pumped to
the rest of the body. They may experience symptoms such as fatigue,
fainting, weakness, coughing, and a swollen abdomen.
"Canine heart rates usually range from 80 to 150 beats per
minute, but when rates drop below 80, pacemakers may be suggested
to provide the users with 'artificial cardiac pacing' thereby
raising and stabilizing their heart rates," Saunders explains.
Veterinary cardiologists performing pacemaker surgery generally
set the pace of the heart at a rate specific to each patient
allowing continuous stimulation for every heartbeat. The
two-hour surgical procedure is often done in one of two ways:
transvenous (through the neck) or epicardial (through the
"The most common method used in veterinary medicine is
transvenous," Saunders said. "This procedure allows us to
create about a three-inch incision in the neck exposing the vessel
and allowing the pulse generator or battery enough room to
Before the pulse generator is introduced, a pacing lead is
inserted into the vessel and passed through the tricuspid valve and
into the right ventricle where it successfully transmits an
electrical charge from the pulse generator to the heart.
Saunders says surgical patients are usually kept overnight for
observation and brought in for a one-month check-up following the
procedure and then evaluated every six months. Pet owners are
advised to keep their animals calm for two to four weeks after
surgery so they can properly heal.
Pet owners are also advised to use a harness instead of a collar
if the pulse generator is placed inside the neck.
"A lead can be pulled out of place if the animal is too
rambunctious during the two-to-four-week healing period," Saunders
said. "If this happens the heart rate may return to its originally
slow rate. Once you pace a dog's heart, it often becomes dependent
on the pacemaker."
This dependency is less of a problem for pets after recovery
because the body forms a type of cast around the pacemaker keeping
it in place. After recovery, pacemakers have a long life and
function like a wristwatch battery.
"If the pacemaker begins to show signs of wear, it will not stop
automatically," Saunders adds. "It will first slow down,
dropping the heart rate. That's why the check-ups are so important.
Canine matters of the heart are best solved by those who love it
most - its owners and its veterinarian," Saunders believes.
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*Above Photo: Dr. Saunders is checking a pacemaker, Middle
Photo: pacemaker next to a quarter, Bottom Photo: X-ray photo of a
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