Topic Overview
An implantable cardioverter-defibrillator (ICD), also known as an
automatic implantable cardioverter-defibrillator (AICD), is a small device that
doctors use to watch for and fix life-threatening abnormal heart rhythms. The
doctor surgically implants the defibrillator under the skin, usually below the
left collarbone. A wire threaded through a large vein connects the device to
the heart.
If you have had a serious episode of an abnormally
fast heart rhythm or are at high risk for having one, you may need an ICD. If
you have coronary artery disease, heart failure, or a problem with the
structure or electrical system of the heart, you may be at risk for an abnormal
heart rhythm.
How does an ICD work?
An ICD continuously
monitors your heart. If it detects a life-threatening rapid heart rhythm, it
sends an electric shock to your heart to restore a normal rhythm. The device
then goes back to its monitoring mode.
After the shock, your
heart may beat very slowly for several minutes. So ICDs also act as pacemakers,
sending weaker shocks that pace the heart if the rate falls below a certain
preset level.
Your doctor sets both the rate at which a shock
will occur and the level of shock needed to convert to a normal rate and
rhythm. If the first shock does not reset your heart rhythm, the device will
send progressively stronger shocks until the heart converts to a normal
rate.
Although an ICD effectively treats life-threatening episodes
of abnormal heart rhythms, it does not prevent them. You will also need to take
a medicine to prevent or at least decrease how often you have abnormal heart
rhythms so that you are not getting too many shocks.
An example of
a life-threatening heart rhythm is ventricular tachycardia.
Living with an ICD
You may feel worried by the
possibility of being shocked. The shock itself can be uncomfortable— it may
feel like you are being kicked in the chest. You may pass out before the device
fires, and you likely won't remember the shock. Be reassured though, that the
shock is life-saving.
Strong electric or magnetic fields can
interfere with the ICD. Most electrical equipment and household appliances
create very weak magnetic fields and do not interfere with ICDs. So you can
safely use most household and office equipment. And you can usually avoid
electrical interference from magnetic or electrical sources by keeping certain
things a few inches away from your pacemaker or ICD. You should completely
avoid things like heavy electrical or industrial equipment.
The
table below lists electrical and magnetic sources that are safe and sources
that you should avoid. This table does not list all magnetic or electrical
sources that you might use. Ask your doctor about the safety of sources not
listed here.
Safety guidelines for ICDsStay away from | - CB or ham radios
- High-voltage power lines. Stay at least
25 ft (7.5 m) away.
- Large magnets
- MRI machines. An MRI uses a magnetic
field and pulses of radio wave energy to make pictures of organs and structures
inside the body.
- Arc welders
- Battery-powered cordless power tools
- Industrial power generators
- Magnets
- Magnetic wands used at airports
- Stereo speakers
|
Use with caution | - Cell phones:
- Do not carry a cell phone in a pocket directly
over the pacemaker or ICD.
- Hold the phone to the ear on the side away from
your device.
- Keep a phone at least
6 in (15 cm) away from the
pacemaker or ICD.
- Keep the following devices at least
12 in (30.5 cm) away from the
pacemaker or ICD:
- Arc welders
- Battery-powered cordless power tools
- Industrial power generators
- Magnets
- Magnetic wands used at airports
- Stereo speakers
- Radio transmitters (including those used in
toys)
|
Safe to use | - Kitchen and bathroom equipment:
- Bathroom appliances (electric razors, curling
irons, and hair dryers)
- Kitchen appliances (such as toasters, blenders,
electric can openers, and refrigerators)
- Microwave, gas, and electric ovens
- Other household items:
- Electric tools (such as drills and table
saws)
- Lawn and garden equipment (such as mowers and
leaf blowers)
- Heating pads and electric blankets
- Washing machines and dryers
- Phones (landline phones including cordless
models)
- Remote controls
- TVs, VCRs, CD players, DVD players
- Office equipment:
- Computers
- Copy machines
- Fax machines
- Printers
|
Driving is something else you need to think about if
you have an ICD. Talk to your doctor about whether you should restrict your
driving. Your doctor will check your medical history as well as your risk of
having another arrhythmia that could make driving unsafe. To help doctors with
this decision, the American Heart Association and Heart Rhythm Society
recommend the following driving restrictions:1, 2
- If you get an ICD because you are at risk for a
life-threatening arrhythmia (but have never had one), you should not drive for
at least 1 week afterward to allow time to heal. After you heal, you can drive
again as long as your ICD has never given you a shock and you have no symptoms
of an arrhythmia. But keep in mind that an arrhythmia could cause you to pass
out (lose consciousness).
- If you get an ICD because you have already had a
life-threatening arrhythmia, you should wait at least 6 months before you drive
again.
- If you have an ICD that has given you a shock for an
arrhythmia, you should wait at least 6 months before you drive again.
It is important to keep your regular follow-up
appointments with your doctor. He or she will check the device to see whether
it has delivered any shocks since your last visit. This will help determine
whether your medicines need to be adjusted. During your follow-up visits, your
doctor will also check the battery and replace it at regular intervals.