Pacemakers
What
is a pacemaker?
A pacemaker
is an artificial device that electrically stimulates the heart's muscle to
cause it to contract to initiate a heart beat. It is a small, lightweight
electrical device surgically placed inside in the upper chest area. A
pacemaker will make your heart beat more regularly. That will help ensure
that enough oxygen and nourishment get to your body's cells. The device
usually only works when it is triggered by an arrhythmia. A pacemaker may
be temporary or permanent, depending on the patient's condition.
An
artificial pacemaker system has two parts: a generator and wire (leads).
The pacemaker generator is a small lithium battery-powered unit. It
produces the electrical impulses that start your heartbeat. The generator
is implanted under your skin through a small incision. A generator is
connected to your heart through tiny wires that are implanted at the same
time. The impulses flow through these leads to your heart and are timed to
flow at regular intervals just as impulses from your heart's natural pacemaker
would.
A pacemaker
senses every heartbeat the patient has and only paces the heart when the
patient's heart rate falls below a pre-set limit. When the pacemaker works
only when it is needed it is called a demand pacemaker. A demand pacemaker
has a sensing device that shuts it off if the heart rate is above a certain
rate. When the heart is beating slower than the pacemaker rate, the sensing
device turns the pacemaker on again. Patients are usually completely
unaware of when the pacemaker is pacing their heart.
When
is a pacemaker indicated?
A pacemaker
is a treatment for a dangerously slow heart rate or arrhythmia. Frequently,
pacemakers are necessary following a heart attack or cardiac surgery.
Without treatment, a slow or irregular heart rate can lead to weakness,
confusion, dizziness, fainting, shortness of breath and even death. Slow
heart rates can be the result of metabolic abnormalities or occur as a
result of blocked arteries to the heart's conduction system. Slow heart
rates can also be a side effect of certain medications.
The sinoatrial node may speed up or slow down the rate at
which it sends its electrical impulse. If the sinoatrial
node slows down the rate, the heart chambers do not contract often enough
to supply the proper amount of blood to your body. This type of arrhythmia
is called bradycardia. If the sinoatrial
node speeds up the rate, the heart chambers do not have enough time to fill
with enough blood to adequately perfuse the body's tissues. This type of
arrhythmia is called tachycardia.
Problems may
also occur with the electrical pathway between the upper heart (atria) and
the lower heart (ventricles). The electrical signals sent out by the sinoatrial node may be delayed in the atrioventricular node (AV node) or may fail to reach
the ventricles all together. This arrhythmia is called heart block. Heart
block may also cause poor timing with the atria and the ventricles. Doctors
call this condition asynchrony. As a result, the ventricles will not fill
with enough blood before contracting.
* There are
several other arrhythmias that may be treated with a pacemaker. These are
only four of the most common reasons why patients need a pacemaker.
What
happens during implantation of a pacemaker?
Fortunately,
having a pacemaker implanted is only a minor surgical procedure. This is
not an open-heart surgery. The procedure is performed with mild sedation
and a local anesthetic. Patients are not put to sleep. An area of skin in
the upper chest area is shaved, scrubbed, and then cleaned with a special
antiseptic. You are given injections of numbing medicine in that area. The
doctor may touch the area and ask you when you start to lose sensation in
your upper chest.
A small,
approximately 2-inch incision is made parallel to and just below the
collarbone. A thin flexible wire (called the lead) is inserted into a vein
that lies just under the collarbone. The doctor gently advances the lead
through that vein under fluoroscopic guidance into the heart. The
fluoroscope may be thought of as a kind of moving X-ray picture. Once the
lead enters the heart, the doctor attaches it to the tissue inside the
heart. At this point, the doctor will test the lead to see if it is in a
suitable place for pacing. The testing is not painful. After the lead test,
your doctor may decide to move the lead and run the test again.
Repositioning and retesting a pacing lead several times is not unusual in
pacemaker surgery.
The other
end of the pacer wires are connected to a "generator" that is
implanted under the skin beneath the collarbone. This generator is about
half an inch deep and one and a half inches wide. The skin is then sutured
closed and the patient leaves the hospital later that same day or the
following day. Pain around the incision is mild and transient and usually
responds to Tylenol. It is possible to feel the pacer generator under the
skin and a slight deformity of the skin can be visually noticed.
What
are possible complications?
Any surgical
procedure includes the possibility of complications. The most typical
complications for pacemaker implantation are not life threatening, but may
require a longer hospital stay or a repeated operation. The most common
complications include bleeding, infection, lead dislodgement, and problems
with the pacemaker working properly. Ask your doctor about potential
complications before your surgery.
Do
pacemaker batteries wear out?
The
pacemaker contains batteries that will wear down over time, just like any
electronic device. The batteries wear down, your pacemaker will slow down,
but it will not stop right away. Most batteries last at least 5 years.
Using a special analyzer, the doctor can detect the first warning that the
batteries are running down. This can be done before you detect any changes
yourself. A sudden major slowing down of your heart rate, which you may
detect, indicates a more serious problem. If that occurs, call your doctor.
Patient
instructions after implantation.
1. SYMPTOMS
TO REPORT TO YOUR DOCTOR
- Fever of 100°F or above, and
or chills
- Unusual drainage, redness,
bleeding, or severe pain around the incision site
- Increased swelling in arm on
same side as pacemaker
- Dizziness, faintness, or
blacking out
- Pulse less than the pre-set
heart rate
2. ACTIVITY
- DO NOT raise affected arm
above shoulder level for 48 hours after surgery
- No large arm movements for 1
month (I.e., no golf, tennis, shoveling, etc.)
- Avoid massaging around the
area of the pacemaker
- Avoid contact sports that
could result in blows to your pacemaker
- If you have steri-strips only, gently wash site with soap and
water, pat dry
- You may shower if you have a
clear plastic dressing over the steri-strips
3. SPECIAL
INSTRUCTIONS
- Inform staff you have a
pacemaker before any X-ray, MRI, or scan
- Inform all doctors/dentists
you see that you have a pacemaker
- Carry your pacemaker
identification card with you at all times
- Wear a medic alert bracelet
or necklace
- Keep all follow up
appointments with your doctor to insure the pacemaker and battery are
functioning properly
- Your pacemaker is sensitive
to strong electrical and magnetic fields
- If you use a cellular phone,
hold the phone on the opposite ear from the pacemaker / 6 inches away
4. THINGS TO
AVOID *Keep the following potential sources of strong electrical or
magnetic fields at lease 30 cm (12 inches) away from your Pacemaker.
- Large stereo speakers
- Strong magnets
- Magnetic bingo wands
- Magnetic wands and detectors
used in airport security
- Industrial equipment like
power generators / arc welders
- Avoid leaning over running
engines
- Many amusement park rides
have strong magnets and should be avoided.
Where
is the test performed?
In the
cardiac catherization lab.
How
long does this test take?
Typically
the procedure takes 1-2 hours to perform
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