Implantable Cardioverter Defibrillator

What Is an Implantable Cardioverter Defibrillator?

An implantable cardioverter defibrillator (ICD) is an electronic device that constantly monitors your heart rhythm.

When it detects a very fast, abnormal heart rhythm, it delivers energy to the heart muscle. This causes the heart to beat in a normal rhythm again.


When Is an ICD Needed?

Ventricular tachycardia and ventricular fibrillation are two life-threatening heart rhythms that cause the heart to beat very fast. These conditions can be fatal if not treated immediately.

Your doctor will recommend an ICD if you’ve had at least one episode of these heart rhythms or are at high risk of developing these types of heart rhythms.

Who Is a Candidate for an ICD?

Together, you and your doctor will determine if an ICD is the right treatment for you.

An ICD may be recommended for patients who:

  • Had a prior episode of sudden cardiacarrest
  • Had a prior episode of ventricular fibrillation
  • Had at least one episode of ventricular tachycardia
  • Had a prior heart attack and have an increased risk for sudden cardiac arrest or sudden cardiac death
  • Have hypertrophic cardiomyopathy
  • Have an increased risk for ventricular fibrillation or ventricular tachycardia due to heart failure



The ICD monitors the heart rhythm, identifies abnormal heart rhythms, and determines the appropriate therapy to return your heartbeat to a normal heart rhythm.

Your doctor programs the ICD to include one or all of the following functions:

  • Antitachycardia pacing (ATP): When your heart beats too fast, a series of small electrical impulses are delivered to the heart muscle to restore a normal heart rate and rhythm.
  • Cardioversion: A low-energy shock is delivered at the same time as your heartbeat to restore a normal heart rhythm.
  • Defibrillation: When the heart is beating dangerously fast, a high-energy shock is delivered to the heart muscle to restore a normal rhythm.
  • Bradycardia pacing: When the heart beats too slow, small electrical impulses are sent to stimulate the heart muscle to maintain a suitable heart rate.

Types of ICDs:

  • Single chamber
  • Dual chamber
  • Biventricular device


Monitors Used During the Procedure

  • Defibrillator/pacemaker/cardioverter: Attached to one sticky patch placed on the center of your back and one on your chest. This allows the doctor and nurse to pace your heart rate if it is too slow or to deliver energy to your heart if the rate is too fast.
  • Electrocardiogram/EKG/ECG: Attached to several sticky electrode patches placed on your chest as well as inside your heart. Provides a picture on the monitors of the electrical impulses traveling through the heart.
  • Blood pressure monitor: Connected to a blood pressure cuff on your arm. Checks your blood pressure throughout the procedure.
  • Oximeter monitor: Attached to a small clip placed on your finger. Checks the oxygen level of your blood.
  • Fluoroscopy: A large X-ray machine will be positioned above you to help the doctors see the leads on an X-ray screen during the procedure.


What Happens Before The Procedure?

You will lie on a bed, and the nurse will start an intravenous (IV) line in a vein in your arm or hand.

To prevent infection and to keep the device insertion site sterile:

  • You will receive an antibiotic through the IV at the beginning of the procedure
  • One side of your chest will be shaved
  • The area will be cleansed
  • You will be covered from your neck to feet with sterile drapes
  • A soft strap may be placed across your waist and arms to keep your hands from touching the sterile area

Will I Be Awake During The Procedure?

Yes. A medication will be given through your IV to relax you and make you feel drowsy, but you will not be asleep during the procedure.

How Is the Device Implanted?

The ICD is usually implanted using the endocardial (transvenous) approach. During the procedure, a local anesthetic is injected to numb the area.

Small incisions are made in the chest where the lead(s) and device are inserted. The lead is inserted through the incision and into a vein, then guided to the heart with the aid of the fluoroscopy machine. The tip of the lead is attached to the heart muscle, while the other end is attached to the pulse generator. The generator is placed in a pocket created under the skin in the upper chest.

When the endocardial approach is used, the hospital recovery time is generally 24 hours.

How Long Does The Procedure Last?

The device implant procedure may last around 2 hours.

Will I Have To Stay At The Hospital?

Yes. You will be admitted to the hospital and stay overnight after the procedure.

You will probably be able to go home the day after your device was implanted, unless the epicardial approach was used during the procedure.


What Are the Possible Risks of the Procedure?

A device implant is generally a very safe procedure. However, as with any invasive procedure, there are risks.

Special precautions are taken to decrease your risks. Please discuss your specific concerns about the risks and benefits of the procedure with your doctor.

Before the Procedure

Taking Medication

If you take Coumadin, the results of your INR test (a blood test to evaluate the blood clotting) must be within a suitable range before the implant procedure can be performed. Usually, you will be instructed to stop taking aspirin or Coumadin (warfarin) a few days before the procedure. Other blood thinners that will need to be held include dabigatran, rivaroxaban, apixaban, and edoxaban.

Your doctor may also ask you to stop taking other medications, such as those that control your heart rate. If you have diabetes, ask the nurse how to adjust your diabetes medications or insulin.

Do not discontinue any of your medications without first talking to your healthcare provider. Ask your doctor which medications you should stop taking and when to stop taking them.

How to Prepare

  • Eat a normal meal the evening before your procedure
  • Do not eat, drink, or chew anything after midnight before your procedure
  • This includes gum, mints, water, etc.
  • If you must take medication(s), take with small sips of water
  • When brushing your teeth, do not swallow any water
  • Remove all makeup and nail polish
  • Do not use deodorant, powder, cream, or lotion on your back or chest

What to Bring

  • A family member to wait with you before the procedure
  • Comfortable, easy-to-fold clothing
  • Toiletries and any other items you would like to make your stay more comfortable. Please note, these will be kept with whomever accompanies you
  • A one-day supply of your prescribed medications
  • Do not bring any jewelry, watches, and/or valuables

After the Procedure

What to Expect After the Procedure

In your hospital room, a special monitor (telemetry monitor) will continually monitor your heart rhythm. The telemetry monitor consists of a small box connected by wires to your chest with sticky electrode patches. The box displays your heart rhythm on several monitors in the nursing unit. The nurses will be able to observe your heart rate and rhythm.

You will also have a monitor (small recorder) attached to your chest with sticky electrode patches. The holter monitor records your heart rhythm for 12 hours to ensure that the pacemaker is functioning properly.

A chest X-ray will be done after the device implant to check your lungs and the position of the device and leads. Before you are discharged, the monitor will be removed, and the results will be given to your doctor.

For your safety, a responsible adult must drive you home. Ask your doctor when you may resume driving.

Care for the Insertion Site

You may feel discomfort at the device implant site during the first 48 hours after the procedure. Call your doctor or nurse if your symptoms are prolonged or severe.

Keep the area where the device was implanted clean and dry. Do not scrub the area. Steri-strips may be covering the wound site; they may be removed 3 weeks after the date of the implant. Do not cover the wound unless you have been instructed to do so. You do not need to keep the wound covered with a bandage. Do not use creams, lotions, or ointments on the wound site.

Look at the area daily to make sure it is healing properly. Call your doctor if you notice:

  • Increased drainage, bleeding, or oozing from the insertion site
  • Increased opening of the incision where the device was implanted
  • Redness, swelling, or warmth around the device insertion site
  • Increased body temperature (greater than 101 degrees Fahrenheit)

You may take a shower 5 days after the procedure.

How the Leads Are Tested

After the leads are in place, they are tested to make sure they are in the right place and working properly. This lead function test is called pacing. Small amounts of energy are delivered through the leads into the heart muscle. This energy causes the heart to contract. You will be asleep for several minutes during the lead function test.

Once the leads have been tested, the doctor will connect them to the device. The rate and settings of your pacemaker are determined by your doctor. After the implant procedure, the doctor uses an external device to program final device settings.

Activity Guidelines

For the first week after your procedure:

  • You may move your arms normally and do not have to restrict arm motion during normal activities. However, do not hold your arms above shoulder level for more than several minutes at a time
  • Stop any activity before you become overtired
  • Try to walk as much as possible for exercise
  • Do not drive for at least one week after your procedure

For the first two weeks after your procedure:

  • Do not lift objects that weigh more than 10 pounds for 2 weeks after the procedure
  • Avoid activities that require pushing or pulling heavy objects
  • Avoid golfing, swimming, tennis, and bowling

Your doctor will tell you when:

  • You can resume driving
  • You can resume more strenuous activities or heavy lifting
  • You can go back to work


A follow-up device check appointment will be scheduled 2-4 weeks after the implant procedure.

This first follow-up appointment is critical. Adjustments will be made that will help your device last longer.

About the Device

Device Checks

Every year, around the anniversary of your device implant, you will have an echocardiogram scheduled along with a complete device check. Since the leads are tested during this appointment, this appointment is different than the telephone transmitter check.

If you have a biventricular pacemaker:

  • After your first follow-up appointment, your pacemaker should be checked every 3 months from home
  • Please make sure that you are set up with a remote monitoring transmitter at the time of your first follow-up for a device check
  • You will receive instructions on how to use remote monitoring during your first follow-up appointment
  • Your biventricular pacemaker also should be checked every 6 months

If you have an implantable cardioverter defibrillator (ICD):

  • After your first follow-up appointment, your device should be checked every 6 months
  • Your device will allow you to use a remote monitoring transmitter
  • You will receive instructions on how to use remote monitoring during your first follow-up appointment

Call your healthcare provider if you have any of these signs of infection:

  • Increased drainage, bleeding, or oozing from the insertion site
  • Increased opening of the incision where the device was implanted
  • Redness, swelling, or warmth around the device insertion site
  • Increased body temperature (greater than 101 degrees Fahrenheit)

The following symptoms may be related to your device:

  • Dizziness
  • Palpitations
  • Fast or slow heart rates
  • Lose or nearly lose consciousness before receiving therapy from the device
  • Have numbness or tingling of the arm closest to the device

If you have a telephone transmitter, please call the transmitter line 8 a.m. – 5 p.m., Monday through Friday, to check your device.

If you have a remote monitor, please call the clinic between the hours of 8 a.m. – 5 p.m., Monday through Friday, and we will instruct you to send us a transmission.

Device Therapy

If you receive therapy from your ICD device:

  • Stay calm or lie down
  • If someone is touching you when the device delivers therapy or fires, he or she may feel a tingling sensation; this is not harmful
  • If possible, ask someone to stay with you until you feel better
  • If you feel fine after the shock, you do not need to seek medical attention
  • Call your doctor within 24 hours

Call your doctor if you:

  • Do not feel well within 5 to 10 minutes after receiving the shock; call your doctor or 9-1-1
  • Received a shock; this needs to be done within 24 hours of the shock
  • Received therapy from the device two or more times in a 48-hour period
  • Received therapy from the device before your 6-8 week follow-up visit

What to Do with Your Device if You Need Surgery

Your cardiologist will tell you if programming changes are needed before or after your surgery.

Your pacemaker should be checked within 3 months before your surgery; please schedule an appointment with your cardiologist.

If you have an ICD, the shock therapies will need to be programmed off during surgery. Please contact your doctor’s office so they can make arrangements for this.

You may or may not be able to tell when your device detects and corrects your heart rhythm. It often depends on the type of therapy you receive from the device:

  • Pacing: You may or may not feel the impulses. They are usually painless
  • Cardioversion: The shock may feel like a thump on the chest, but it only lasts for a moment
  • Defibrillation: The shock may feel like a kick in the chest, but it only lasts for a moment. Some patients describe the feeling as a shock from an electrical outlet

Most of the time, you will be awake for the therapy, but you may lose consciousness prior to the shock.

How Long Your Device Will Last

Depending on how often they are used, pacemakers usually last 8-10 years, while ICDs and CRT devices last 6 to 8 years.

By keeping your follow-up appointments, your doctor can monitor the function of your device and anticipate when it needs to be changed.

Living with the Device

Most household appliances do not interfere with pacemakers.

Cell Phones

While your cell phone may not affect your pacemaker, to be safe, use your cell phone on the side opposite of where the device was implanted. Cell phones should not be placed directly against the chest or on the same side as your device.


Certain types of headphones may contain a magnetic part that can affect pacemaker function. Keep headphones 1-2 inches away from your pacemaker. Do not keep your headphones in the breast pocket of a shirt or drape them around your neck.

Security Devices

If you must pass through entrances where anti-theft devices or metal detectors are being used for security, be sure to walk quickly through them. If handheld metal detector scanning is necessary, tell the security personnel that you have a pacemaker. You should not hold the metal detector near the device for any length of time.

Powerful Magnets, Magnetic Fields, and Equipment

You will need to avoid strong electric or magnetic fields, such as:

  • Some industrial equipment
  • Ham radios
  • High-intensity radiowaves
  • Arc resistance welders

In strong magnetic fields, the device stops monitoring your heart rhythm. Once you are out of these fields, normal device function resumes and there is no damage to the device.

Magnetic Resonance Imaging (MRI)

Some devices are compatible with MRIs. If you have been instructed to have an MRI, contact your implanting physician about the type of device that you have implanted and if this type of testing is safe for you.

Hybrid Cars

Stay about 2 feet away from the engine, and do not keep your smart key near your device. Do not put it in a pocket that is over your device.

We know these are very conservative recommendations, and there have been no reports of adverse outcomes due to exposure to either of these environments. However, this information has been recommended by current sources and is the best information we have at this time.

If you have any questions about the use of equipment around your device, check your device manufacturer website and ask your doctor or nurse.

Electric Fence for Pets

Stay at least a foot away.

We know these are very conservative recommendations, and there have been no reports of adverse outcomes due to exposure to either of these environments. However, this information has been recommended by current sources and is the best information we have at this time.

If you have any questions about the use of equipment around your device, check your device manufacturer website and ask your doctor or nurse.

Carry an ID Card

You will receive a temporary ID card that tells you what type of device and leads you have, the device manufacturer, the date of the device implant, and the name of the doctor who implanted the pacemaker.

Within three months, you will receive a permanent ID card from the device company. It is important to carry this card at all times in case you need medical attention or to tell people you have a pacemaker.

Let your healthcare providers know you have an implanted device. In rare occasions they may want to adjust your treatment plan because you have a pacemaker or defibrillator.

Airport Security

Should the security personnel use a wand to clear people, show them your card, and ask them to avoid placing the wand over your implanted heart device. Ask security if there is another method for clearance.