(Cardiac Implantable Devices, Defibrillator)

An ICD is an electronic device that is placed in your body to help control the speed and pattern of your heart rate by constantly monitoring your heart rate and 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.

The ICD is made up of two parts, a generator and leads.

The generator houses the battery and a tiny computer. Energy is stored in the battery until it is needed. The computer receives information from the leads to determine what rhythm is occurring.

Leads are tiny wires that monitor the heart’s rhythm and delivery energy from the generator for pacing, cardioversion and/or defibrillation.

There are different types of ICDs:

• Single chamber ICD: A lead is attached in the right ventricle. If needed, energy is delivered to the ventricle to help it contract normally
• Dual chamber ICD: Leads are attached in the right atrium & the right ventricle. Energy is delivered first to the right atrium and then to the right ventricle, helping your heart to beat in a normal sequence
• Biventricular ICD: Leads are attached in the right atrium, the right ventricle and the left ventricle. This technique helps the heart beat in a more balanced way and is specifically used for patients with heart failure.

The ICD is an amazing little computer. It 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:

• Anti-tachycardia Pacing (ATP) – When the 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.

The procedure is used for:

• People who have had an episode of sudden cardiac death or ventricular fibrillation
• People who have had a heart attack and are at high risk for sudden cardiac death
• People who have hypertrophic cardiomyopathy and are at high risk
• People with at least one episode of ventricular tachycardia

Preparing for the procedure:

• Please inform your doctor if you have any allergies. If indicated, he or she will prescribe any medications needed to reduce the risk of an allergic reaction.
• Ask your doctor what medications you are allowed to take. Your doctor may ask you to stop certain medications one to five days before your test (such as aspirin products). If you are diabetic, ask your doctor how you should adjust your diabetic medications.
• Do not eat or drink anything after midnight the evening before your test. If you must take medications, drink only with a sip of water.
• When you come to the hospital, wear comfortable clothes. You will change into a hospital gown for the procedure. Leave all jewelry or valuables at home.
• Please arrange for someone to drive you home

What to expect during the procedure:

• You will lie on a bed and the nurse will start an intravenous line (IV) into your arm or hand. This is so you may receive medications and fluids during the procedure. You will be given an antibiotic to prevent infection and a medication through your IV to relax you and make you drowsy, but it will not put you to sleep.

You will be taken to a sterile room with special cameras for the procedure. The nurse will connect you to several monitors that will allow the doctor and nurse to check your heart rhythm, blood pressure and other measurements during the pacemaker implant.

Your left or right side of your body, from your neck to your groin will be shaved and cleansed with a special soap. Sterile drapes are used to cover you from your neck to your feet. A strap will be placed across your waist and arms to prevent your hands from coming in contact with the sterile field.

A small incision will be made in your chest just below your collarbone. A pocket is made under the skin for the generator to sit in. The lead is then threaded into the vein under the collarbone and placed, with the help of x-ray monitors, into your heart. Next, the generator is programmed to treat your specific rhythm problem, and its functioning is tested. Then, the leads are attached to the generator. The generator is then placed into the pocket, and the incision is closed with stitches.

On rare occasion, it may be necessary for your doctor to implant your ICD by epicardial approach (outside your heart). This requires open heart surgery. Instead of placing the lead through a vein and guiding it to the heart, it is sewn onto the heart. Your doctor will decide if this approach is necessary for you.

The ICD implant takes about two to five hours to perform.

What to expect after the procedure:

• After your ICD insertion you will stay in the hospital a day or two. The nurses will monitor your heart rate and rhythm. The length of your hospital stay depends on the type of ICD procedure you had. The morning after your implant, you will have an EKG, blood tests and a chest x-ray to ensure the leads and/or patches and ICD is in the proper position. You will also go to the electrophysiology lab to have your ICD checked. This will involve testing the ICD and programming it to your needs.
• It is normal for the incision to be a bit tender and bruised. Keep your wound clean and dry. You may move your arm normally and can do most activities when you return home. You will need to avoid lifting objects weighing more than 20 pounds, or pushing/pulling heavy objects.
• After five days, you may take a shower. Look at your wound every day to make sure it is healing. Call your doctor if you notice redness, drainage, severe pain, swelling, fever, or chills to see if further evaluation is indicated.
• You will have a slight bulge under the skin where the generator is located. It will not be noticeable under clothes. If the ICD implant is in your abdomen, avoid wearing tight fitting clothing or tight belts so your wounds will not be irritated.
• You will be given information about your ICD identification which will include the type or ICD and leads you have, the date of the implant and the name of the doctor who performed the procedure. In about three months you will receive a permanent card from the company. It is important that you carry this card at all times in case you need medical attention.
• Most electrical devices, such as microwave ovens, do not interfere with ICD function. However the following guidelines should be followed:
• Do not undergo any tests that require magnetic resonance imaging (MRI). You may have CT (“CAT”) scans done if necessary
• Avoid strong electric or magnetic fields such as some industrial equipment, high output ham radios, high intensity radiowaves (found near large electrical generators, power plants or radiofrequency transmission towers), and arc or resistance welders.
• You should stay at arm’s length away from less powerful electric or magnetic fields such as large magnets, stereo speakers, airport security wands, antennas used in ham or CB radios.
• Keep cellular phones at least 6 inches from your ICD and not on the same side as your ICD.
• If you have concerns about your job or activities, ask your doctor.
• You may or may not be aware of when your ICD detects and corrects your heart rhythm. Often it depends on the type of therapy you receive:
• Pacing – you may or may not feel the impulses – usually they are not detectable
  Cardioversion – shock feels like a thump on the chest; discomfort does not linger
  Defibrillation – you may be unconscious (passed out) and not feel the shock. If you are awake, the shock feels like a kick in the chest; felt for only a moment.
• Stay calm If you receive a shock. Sit or lie down. And ask someone to stay with you.
  If you do not feel well after the shock, call your doctor or an ambulance. If you feel fine after the shock, you do not need to seek immediate medical attention but you need to call your doctor
  within 24 hours.
• If someone is touching you when the ICD fires, they may feel a tingling feeling. This is not harmful to them.
• Regular follow-up is important after an ICD implant. Your doctor will tell you how often you will need to have the ICD checked. During ICD checks, the doctor will determine if the ICD had detected or treated any abnormal heart rhythms and will check the ICD battery. These visits are very important. You will also need to see a cardiologist at least once a year.