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Why is the doctor performing this procedure?
To monitor
an abnormally beating heart, either one that beats too fast (tachycardia), too
slow (brachycardia) or irregularly (atrial fibrillation). These abnormal heart
beats are referred to as arrhythmias.
What is an AICD?
An AICD is a device that monitors a
person's heartrate. They are generally implanted into heart failure patients.
The device is programmed to perform the following tasks: speed up or slow down
your heart, depending upon the heart rateThe AICD gives your heart a shock
if you start having life threatening arrhythmias or an abnormally high heart
rate. Arrhythmias occur when your heart does not beat normally. Some arrhythmias
can cause the heart to completely stop beating. The shock given by the AICD can
make the heart start beating normally again. An AICD can also make your heart
beat faster if your heart is not beating fast enough.
There are different kinds of AICDs, but they all have 2 parts: electrodes
(thin flexible wires) and a generator. The electrodes or "leads" sense or watch
the heart's electrical activity. The generator is the battery power source and
the "brains" of the AICD. It is a small metal can about the size of a deck of
cards. The generator stores information about any arrhythmias you have. The
generator also keeps track of how often it needs to give your heart a shock.
Some AICDs also function as pacemakers for heart rates that are too slow or too
fast.
When is an AICD indicated?
Your doctor has recommended
you for an AICD system for one or more of the following reasons:
- At least one episode of Ventricular Tachycardia (VT)
or Ventricular Fibrillation (Vfib)
- Previous cardiac arrest or abnormal heart rhythm that
has caused you to pass out
- A fast heart rhythm that keeps returning and could
cause death
- A fast heart rhythm that cannot be cured by surgery
- A fast heart rhythm that cannot be controlled with
medications
- Severe side effects from medications
What happens during implantation of an AICD?
Prior to
implantation of an AICD, an electrophysiological study (EP study) may be
performed. An EP study is used to help decide whether to use an AICD or whether
to use drugs for treatment.
The newer AICD units can be implanted without
major surgery. The procedure is performed under local anesthesia, but sometimes
it is done under general anesthesia. You will be hooked up to an intravenous
(IV) line and will receive sedation. Before the doctor makes an incision, your
upper chest will be cleaned and your torso draped. Your arms may be loosely
strapped to prevent movement during the testing of the AICD.
The doctor will
make an incision in your upper chest area below the collarbone. A wire will be
inserted through a vein into your heart. Sometimes more than one wire is used.
The doctor will create a "pocket" in your chest, where the AICD is inserted. The
AICD is connected to the wires. The doctor will test the AICD by creating an
arrhythmia and then observing whether the AICD delivers the required therapy.
Later that day, or the next day, your AICD system will be checked and tested
again with a computer called a "programmer." This procedure is called
"noninvasive programmed stimulation" or "pre-discharge testing." You will
receive sedation. The doctor will provoke an arrhythmia to see if the device
works. The AICD will deliver a shock (defibrillation). The staff will fine-tune
the equipment.
Recovery time after implantation of newer AICD units is quite short. Hospital
stays are rarely longer than 3 or 4 days and there is quick return to prior
activity levels. People with AICDs must continue to follow their doctor's
recommendations regarding medication, diet, and exercise.
Prior to discharge,
you will be shown how to examine your incision site. You should look for signs
of infection each day such as increased redness, increased tenderness, swelling
around the incision, drainage from the incision. You should also report a fever
over 100°F that lasts longer than 24 hours. You will also receive instructions
on your AICD.
Do AICD batteries wear out?
The AICD pulse generator runs
on a battery. The battery provides the energy needed to monitor your heart
rhythm, pace the heart or deliver electrical therapy. Just like a battery you
use with your electronic equipment, the battery can wear down over time. How
long the AICD pulse generator will last is dependent on what settings are
programmed into the system. It is also affected by how much therapy you receive.
Your doctor will open the pocket of skin where the pulse generator is located
to replace your AICD pulse generator. The old pulse generator will be unplugged
from the leads. The leads are checked to make sure they are still working
properly. Then they are connected to the new AICD pulse generator. A test is
preformed to make sure the new system is working properly.
Once the doctor
knows the AICD is working properly, he/she will stitch the pocket of skin
closed. The entire procedure takes about an hour. It is considered a minor
operation, and you should be able to return to normal activities soon.
Where is the test performed?
In a cardiac catherization
lab
How long does this test take?
Typically the procedure
takes 1-2 hours to perform
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