What is an implantable cardioverter defibrillator?
An implantable cardioverter defibrillator (ICD) is a small electronic device connected to the heart. It is used to continuously monitor and help regulate potentially fast and life-threatening electrical problems with the heart.
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 pacing that corrects a fast rhythm and promotes a normal heartbeat, or a shock (defibrillation) that resets the heart rhythm to prevent sudden cardiac arrest. An ICD also records and stores information about your heart rhythm and therapies delivered by the ICD for your doctor to review.
Most people are unaware when the ICD is pacing the heart. But, a defibrillation shock is described by many as feeling like a "kick in the chest."
The ICD can also be programmed to work 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. The ICD can act as a pacemaker any time the heart rate drops below a preset rate.
Why might I need an implantable cardioverter defibrillator?
You may need an ICD if you have survived sudden cardiac arrest due to ventricular fibrillation, or have fainted due to ventricular arrhythmia, or if you have certain inherited heart conditions.
An ICD is generally needed for those at high risk of cardiac arrest due to a ventricular arrhythmia. This includes people 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.
What are the risks of an implantable cardioverter defibrillator?
Possible risks of ICD insertion include:
- Bleeding from the incision or catheter insertion site
- Damage to the blood vessel at the catheter insertion site
- Infection of the incision or catheter site
- Tearing of the heart muscle
- Collapsed lung
- Dislodging of the leads requiring another procedure to reposition the leads
If you are pregnant or think that you could be, or are currently breastfeeding, tell your healthcare provider.
If you are allergic to or sensitive to any medicines or latex, tell your healthcare provider.
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 healthcare provider before the procedure.
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.
Tell your nurse right away 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 help. The nurse will help you the first time you get up, and will check your blood pressure while you are lying in bed, sitting, and standing. 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.
Your arm may be in a sling for a day or so. How long you will need to wear a sling will depend on your provider. Some people are asked to wear it at night while they sleep after the first couple of days but can take it off during the day.
The insertion site may be sore or painful, and pain medicine may be given if needed.
After the procedure, a chest X-ray is often done to check the lung and make sure the systems are stable.
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.
If the procedure is done on an outpatient basis, you may be able to leave after you have completed the recovery process. However, it is common to spend at least 1 night in the hospital after ICD implantation for observation.
Arrange to have someone drive you home from the hospital after your release.
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.
Avoid lifting or pulling on anything for a few weeks. You may be told 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 tells you differently.
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 says it's OK. 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 told 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 job, your overall health, and your progress will determine how soon you may return to work.
After implantation, your ICD will require regular evaluation (called an interrogation) to evaluate its function and battery status, and to check for any significant events stored by the device. Your doctor will tell you when and how this is done.
A home monitor may be provided to you that can communicate with your ICD wirelessly. Information about ICD function can then be related to your doctor over the internet.
Tell your doctor right away if you have any of the following:
- Fever or chills
- Increased pain, redness, swelling, or bleeding or other drainage from the insertion site
- Chest pain or pressure, nausea or vomiting, profuse sweating, dizziness or fainting
- ICD shock
- If your device generator feels loose or like it is wiggling in the pocket under the skin
Your doctor may give you other instructions after the procedure, depending on your particular situation.
Living with an ICD
Take the following precautions when you have an ICD implanted. 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 ID bracelet showing that you have an ICD.
- If you travel by air, 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. Do not lean on or stand in this equipment. But it is OK to pass quickly through the detection system.
- Avoid large magnetic fields such as power generation sites and industrial sites, such as automobile junkyards that use large magnets.
- If an MRI has been recommended for you, contact your doctor. Some newer ICDs are compatible with MRI scanners with some restrictions.
- Do not use diathermy (the use of heat in physical therapy to treat muscles). Do not use a heating pad directly over your ICD.
- Avoid transcutaneous electrical nerve stimulation (TENS) therapy. Talk to your doctor if you are considering this treatment.
- 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 ahead of the operation that you have an ICD. Also, consult with your cardiologist before the procedure to find out if you need any special preparation.
- When involved in a physical, recreational, or sporting activity, 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 keep them at least 6 inches away from your ICD. Avoid carrying a cell phone in your breast pocket over your ICD.
- Always see your doctor when you feel ill after an activity, or when you have questions about beginning a new activity.
- Always talk to your doctor if you have any questions concerning the use of equipment near your ICD.