Automatic Implantable Cardioverter Defibrillators (AICD or ICD)
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.
What
are possible complications?
Any
surgical procedure includes the possibility of complications. The most
typical complications for AICD 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 AICD working properly. Ask your doctor about potential
complications before your surgery.
The
defibrillator unit can cause local discomfort. The most common long-term
complication is the delivery of shocks when the patient does not need
them. This is less of a problem with more recent devices. The patient is
usually quite aware of each shock, even though it is very short in
duration. The patient's doctor should be notified of every shock the patient
feels. When the batteries have depleted their energy, the pulse generator
must be replaced. Replacement of the pulse generator requires minor
surgery. Cost should also be considered a factor.
What
should I do if I receive a shock?
If you have
symptoms of a fast heart rate, it is likely that your AICD will deliver a
shock within a few seconds. There is not usually much time to react. Some
patients describe the shock as a feeling like a quick click or hiccup;
others feel a thump and have described it like a blow to the chest.
Whatever you feel, you should adhere to the following guidelines:
- Remain calm and find a
place to sit or lie down.
- If possible, have someone
who is prepared to provide you with CPR stay with you throughout the
event, should you need it.
- Have a friend or family
member call 9-1-1 if you remain unconscious for more than one
minute.
- If you are conscious but
do not feel well after the shock, have someone call your doctor.
Follow your doctor's orders carefully.
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 AICD
- Dizziness, faintness, or
blacking out
- Anxiety or depression that
interferes with your everyday activities
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 AICD
- Avoid contact sports that
could result in blows to your AICD
3.
SPECIAL INSTRUCTIONS
- Inform staff you have an
AICD before any X-ray, MRI, or scan
- Inform all
doctors/dentists you see that you have an AICD
- Carry your AICD
identification card with you at all times
- Wear a medic alert
bracelet or necklace
- Keep regular doctor's
appointments. The frequency will depend on the type of device.
Devices may require occasional adjustments to ensure peak operating
efficiency.
- If you use a cellular
phone, hold the phone on the opposite ear from the AICD, at least 6
inches away. Do not carry cellular phones in a pocket or close to
the AICD generator.
4.
THINGS TO AVOID
* Keep the following potential sources of strong electrical or magnetic
fields at lease 30 cm (12 inches) away from your AICD.
- Large stereo speakers
- Strong magnets
- Magnetic bingo wands
- Magnetic wands and
detectors used in airport security
- Nerve stimulators (TENS
units)
- Touching the spark plugs
or distributor wires of a running car or lawn mower
- Industrial equipment like
power generators / arc welders
- Battery-powered cordless
power tools such as screwdrivers, drills, etc.
- Avoid leaning over running
engines
- Many amusement park rides
have strong magnets and should be avoided.
- Check with your doctor
about using radio frequency, remote-controlled transmitters used for
toy cars and airplanes.
YOUR AICD
SYSTEM MAY MAKE SOUNDS IF YOU ARE TOO CLOSE TO A MAGNET. THE DEVICE MAY
BEEP (ABOUT ONCE PER SECOND) OR MAKE A CONTINUOUS TONE. MOVE AWAY FROM
THE OBJECT OR LOCATION IMMEDIATELY AND CALL YOUR DOCTOR.
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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