What is an implantable cardioverter defibrillator?
An implantable cardioverter defibrillator (ICD) is a small electronic device 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 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.
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.
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.