The ICD, about the size of a stopwatch, is implanted under the skin just below the collarbone. It consists of a pulse generator and wires, called leads. The pulse generator contains the battery and a tiny computer. One or more lead wires connect the pulse generator to specific locations in the heart.
The ICD responds to irregular life-threatening heart rhythms from the lower chambers of the heart with either anti-tachycardia pacing (ATP) consisting of low energy impulses to promote a normal heartbeat, or shock therapy with high-energy impulses, to prevent sudden cardiac arrest. An ICD can record and store information about your heart rhythm and therapies delivered by the ICD for your doctor to review.
ATP involves rapid regular pacing impulses delivered in order to correct and restore normal rhythm by overtaking a fast irregular rhythm. Most people are unaware when this therapy is being delivered.
Defibrillation is described by many as feeling like a "kick in the chest."
The ICD can also be programmed to function as a basic pacemaker as needed. Sometimes after a shock is delivered, the heart may beat too slowly. The ICD has a "back-up" pacemaker, which can stimulate the heart to beat faster until the normal heart rhythm returns. Additionally, an ICD can act as a pacemaker not only after a shock is delivered, but also any time the heart rate drops below a preprogrammed rate.
Why might I need an implantable cardioverter defibrillator?
An ICD may be inserted in survivors of sudden cardiac arrest due to ventricular fibrillation, syncope (fainting) due to ventricular arrhythmia, or some inherited heart conditions.
It is generally inserted for those at high risk of cardiac arrest due to a ventricular arrhythmia (individuals with heart failure who have problems with the contraction of the heart, such as abnormal left ventricular ejection fraction).
There may be other reasons for your doctor to recommend an ICD insertion.
What are the risks of an implantable cardioverter defibrillator?
Possible risks of ICD insertion include, but are not limited to, the following:
Bleeding from the incision or catheter insertion site
Damage to the vessel at the catheter insertion site
Infection of the incision or catheter site
Perforation of the heart muscle
Pneumothorax. If the lung is inadvertently punctured during the procedure, air becomes trapped in the pleural space between lung and chest wall. This can interfere with breathing and in extreme cases may cause the lung to collapse.
If you are pregnant or suspect that you may be pregnant, you should tell your health care provider. If you are breastfeeding, you should notify your healthcare provider.
If you are allergic to or sensitive to medications or latex tell your doctor.
Lying still on the procedure table for the length of the procedure may cause some discomfort or pain.
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure.
How do I get ready for an implantable cardioverter defibrillator?
Your doctor will explain the procedure to you and ask if you have any questions.
You will be asked to sign a consent form that gives your permission to do the test. Read the form carefully and ask questions if something is not clear.
Tell your doctor if you are sensitive to or are allergic to any medications, iodine, latex, tape, or anesthetic agents (local and general).
You will need to fast for a certain period prior to the procedure. Your doctor will tell you how long to fast, usually overnight.
If you are pregnant or suspect that you are pregnant, you should tell your doctor.
Tell your doctor of all medications (prescription and over-the-counter) and herbal or other supplements that you are taking.
Tell your doctor if you have heart valve disease, as you may need to receive an antibiotic prior to the procedure.
Tell your doctor if you have a history of bleeding disorders or if you are taking any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting. It may be necessary for you to stop some of these medications prior to the procedure.
Your doctor may request a blood test prior to the procedure to determine how long it takes your blood to clot. Other blood tests may be done as well.
You may receive a sedative prior to the procedure to help you relax.
Based on your medical condition, your doctor may request other specific preparation.
How is a cardioverter defibrillator implanted?
An implanted cardioverter defibrillator insertion may be done on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your doctor’s practices.
Generally, an ICD insertion follows this process:
You will be asked to remove any jewelry or other objects that may interfere with the procedure.
You will be asked to remove your clothing and will be given a gown to wear.
You will be asked to empty your bladder prior to the procedure.
An intravenous (IV) line will be started in your hand or arm prior to the procedure for injection of medication and to administer IV fluids, if needed.
You will be placed on your back on the procedure table.
You will be connected to an electrocardiogram (ECG) monitor that records the electrical activity of the heart and monitors the heart during the procedure using small, adhesive electrodes. Your vital signs (heart rate, blood pressure, breathing rate, and oxygenation level) will be monitored during the procedure.
The areas where the electrodes patches are placed are cleaned, and in some cases, hair may be shaved or clipped. If there is excessive hair at the surgical site, it may be clipped off.
Large electrode pads will be placed on the front and back of the chest.
You will receive a sedative medication in your IV before the procedure to help you relax. However, you will likely remain awake during the procedure.
The ICD insertion site will be cleansed with antiseptic soap.
Sterile towels and a sheet will be placed around this area.
A local anesthetic will be injected into the skin at the insertion site.
Once the anesthetic has taken effect, the doctor will make a small incision at the insertion site.
A sheath, or introducer, is inserted into a blood vessel, usually under the collarbone. The sheath is a plastic tube through which the ICD lead wire will be inserted into the blood vessel and advanced into the heart.
It will be very important for you to remain still during the procedure so that the catheter does not move out of place and to prevent damage to the insertion site.
The lead wire will be inserted through the introducer into the blood vessel. The doctor will advance the lead wire through the blood vessel into the heart.
Once the lead wire is inside the heart, it will be tested to verify proper location and that it works. There may be one, two, or three lead wires inserted, depending on the type of device your doctor has chosen for your condition. Fluoroscopy, (a special type of X-ray that will be displayed on a TV monitor), may be used to assist in testing the location of the leads.
The ICD generator will be slipped under the skin through the incision (just below the collarbone) after the lead wire is attached to the generator. Generally, the generator will be placed on the nondominant side. (If you are right-handed, the device will be placed in your upper left chest. If you are left-handed, the device will be placed in your upper right chest).
The ECG will be observed to monitor ICD function. Certain tests may then be performed to assess the device function.
The skin incision will be closed with sutures, adhesive strips, or special glue.
A sterile bandage or dressing will be applied.
What happens after an implantable cardioverter defibrillator?
In the hospital
After the procedure, you may be taken to the recovery room for observation or returned to your hospital room. A nurse will monitor your vital signs.
You should immediately inform your nurse if you feel any chest pain or tightness, or any other pain at the incision site.
After the period of bed rest has been completed, you may get out of bed with assistance. The nurse will assist you the first time you get up, and will check your blood pressure while you are lying in bed, sitting, and standing. You should move slowly when getting up from the bed to avoid any dizziness from the period of bed rest.
You will be able to eat or drink once you are completely awake.
The insertion site may be sore or painful, and pain medication may be administered if needed.
Your doctor will visit with you in your room while you are recovering. The doctor will give you specific instructions and answer any questions you may have.
Once your blood pressure, pulse, and breathing are stable and you are alert, you will be taken to your hospital room or discharged to home.
If the procedure is performed on an outpatient basis, you may be allowed to leave after you have completed the recovery process. However, it is common to spend at least one night in the hospital after ICD implantation for observation.
You should arrange to have someone drive you home from the hospital following your procedure.
You should be able to return to your daily routine within a few days. Your doctor will tell you if you need to take more time in returning to your normal activities. In addition, you should avoid lifting or pulling on anything for a few weeks. You may be instructed to limit movement of the arm on the side that the ICD was placed, based on your doctor's preferences.
You will most likely be able to resume your usual diet, unless your doctor instructs you differently.
It will be important to keep the insertion site clean and dry. You will be given instructions about bathing and showering.
Your doctor will give you specific instructions about driving. You will not be able to drive until your doctor gives you approval. These limitations will be explained to you, if they are applicable to your situation.
You will be given specific instructions about what to do the first time your ICD delivers a shock. For example, you may be instructed to dial 911 or go to the nearest emergency room in the event of a shock from the ICD. Calming yourself with slow deep breaths can be helpful if you are anxious after a shock.
Ask your doctor when you will be able to return to work. The nature of your occupation, your overall health status, and your progress will determine how soon you may return to work.
After implantation, your ICD will require regular evaluation or interrogation to evaluate its function and battery status, and to assess for any significant events stored by the device. Your doctor will provide details regarding recommended frequency and mode of evaluation.
Notify your doctor to report any of the following:
Fever and/or chills
Increased pain, redness, swelling, or bleeding or other drainage from the insertion site
Chest pain or pressure, nausea and/or vomiting, profuse sweating, dizziness and/or fainting
Your doctor may give you additional or alternate instructions after the procedure, depending on your particular situation.
Living with an ICD
The following precautions should always be considered. Discuss the following in detail with your doctor, or call the company that made your device:
Always carry an ID card that states you have an ICD. In addition, you may want to wear a medical identification bracelet indicating that you have an ICD.
In the event of air travel, inform security screeners that you have an ICD before going through the metal detector. (It may help to say you have a pacemaker – which is true as pacemaker functions are built into ICDs – because security may not know what an ICD is.) In general, airport security detectors are safe for pacemakers and ICDs, but the small amount of metal in the device and leads may trigger the alarm. If you are selected for additional screening, politely remind the screener that the security wand contains a magnet, which may interfere with the programming or function of the ICD (pacemaker) if it is held over the device for more than a few seconds.
Anti-theft systems or electronic article surveillance (EAS) used in department stores may interact with an ICD. The American Heart Association recommends you should not lean on or stand in this equipment but should pass quickly through the detection system.
You may not have a magnetic resonance imaging (MRI) procedure. You should also avoid large magnetic fields such as power generation sites and industrial sites, such as automobile junkyards that use large magnets.
Abstain from diathermy (the use of heat in physical therapy to treat muscles). Do not use a heating pad directly over your ICD.
Turn off large motors, such as cars or boats, when working on them as they may create a magnetic field.
Avoid high-voltage and radar machinery, such as radio or television transmitters, electric arc welders, high-tension wires, radar installations, or smelting furnaces.
If you are scheduled for surgery, let the surgeon know well prior to the operation that you have an ICD. Also, you should consult with your cardiologist prior to the procedure to find out if any special preparation should be done prior to or during surgery, as the electrocautery device which controls bleeding may interfere with the ICD.
When involved in a physical, recreational, or sporting activity, you should protect yourself from trauma to the ICD. A blow to the chest near the ICD can affect its functioning. If you are hit in that area, you may want to see your doctor.
Cell phones are generally safe to use, but you should keep them at least 6 inches away from your ICD. Avoid carrying a cell phone in your breast pocket over your ICD.
Always consult your doctor when you feel ill after an activity, or when you have questions about beginning a new activity.
Always consult your doctor if you have any questions concerning the use of equipment near your ICD.
Before you agree to the test or the procedure make sure you know:
The name of the test or procedure
The reason you are having the test or procedure
The risks and benefits of the test or procedure
When and where you are to have the test or procedure and who will do it
When and how will you get the results
How much will you have to pay for the test or procedure