Cardiovascular Institute and Center for Cardiovascular Health
Automatic Implantable Cardioverter Defibrillator (AICD)An automatic implantable cardioverter defibrillator (AICD), sometimes known as an ICD, continuously monitors your heart for any rapid and/or irregular heart rhythms (arrhythmias) When the AICD detects an arrhythmia, it delivers therapy to your heart automatically.
What causes an arrhythmia?You might have been born with an arrhythmia (congenital). It may be caused by coronary artery disease or by damage to the heart muscle following a heart attack. Arrhythmias also occur in individuals with weakened heart muscle (cardiomyopathy). At what age would I need an AICD?AICDs have been implanted in people from age ten through their eighties. The average person is in his or her sixties. Why does my doctor want me to have this implant?Most likely your doctor ordered this procedure for one of two reasons. You might have survived a sudden cardiac death (SCD) experience. Sudden cardiac death may be caused by a variety of cardiovascular diseases including a serious arrhythmia. If not, you probably underwent an Electrophysiology Study (EPS) which is a test designed to diagnose arrhythmias. You might have had other diagnostic tests including: an electrocardiogram, an echocardiogram, or holter monitoring. You may have an arrhythmia called "ventricular tachycardia" (VT or V-tach). This consists of very fast but regular heart beats originating from the lower chamber of your heart. Your heart will not pump as efficiently as it does during a normal rhythm. You may feel it pound. You may feel faint or dizzy. You may have an arrhythmia called, "ventricular fibrillation" (VF) . VF is an unstable heart rhythm during which your heart beats in a disorganized manner. Your heart will stop pumping blood and you will suffer a temporary loss of oxygen. You will usually pass out within a few seconds. These conditions are life threatening without treatment. How does the AICD deliver treatment?If your heart goes into VF, the AICD can deliver an electrical shock to it which stops the quivering of the heart, and restores normal heart beats. This is called, "Defibrillation." If your heart goes into VT, the AICD can deliver smaller electrical shocks to stop the fast rhythm and restore normal heart beats. This is called, "Cardioversion." If your heart goes into VT, some AICD's can also deliver a series of small, rapid pacing impulses to it. This can restore normal heart rhythm. The AICD will not deliver further treatment or shock. You may not feel this. This is called "Anti-Tachycardia Pacing (ATP)." Finally, perhaps your heart beats too slowly. This is called bradycardia. If you have bradycardia, the AICD will work as a pacemaker. It will deliver small impulses to pace your heart until it recovers and maintains a normal rate. What does defibrillation feel like?If you fainted or became unconscious shortly after the VF rhythm started., you will not feel the high energy shocks. If you are conscious, the shock may feel like a 'kick in the chest'. Usually, the shock comes suddenly. The sensation lasts for only a fraction of a second. Reactions vary. You may find it reassuring; you may find it briefly uncomfortable. What does cardioversion feel like?These low-energy shocks are stronger than pacing pulses. You may find cardioversion uncomfortable.. It may feel like a "thump on the chest." What does ATP feel like?You may not feel anything at all with anti-tachycardia pacing. You may feel a fluttering in your chest. You may feel slight discomfort. What does bradycardia pacing feel like?These pacing pulses are very low energy. You probably will not feel them. Where is the AICD implanted?Usually, the AICD is implanted on the left or right upper portion of your chest muscle just below the collar bone. Sometimes, it is implanted in the abdominal area. The AICD is light in weight and smaller than the palm of a man's hand. It consists of a generator (computer and battery) and one or more leads (wires). Will I need to sign a consent form?After your doctor has explained the risks of the operation, you will be asked to sign a consent form. You can prevent some of the risks. For example, if you move your shoulder normally after the AICD is implanted, you can prevent it from becoming stiff or "frozen". Tell your doctor if you taking a blood thinner like Coumadin. You will have to stop taking it and aspirin, for a week to ten days before surgery and for two weeks after surgery to prevent internal bleeding. What if I have questions about the AICD?Before the operation, you will meet with a doctor or nurse who will explain the operation, how the AICD works, and how it will affect your life. Do not hesitate to ask questions and voice your concerns. Some hospitals allow you to bring family along, so that the doctor or nurse can answer their questions, too. What happens in the hospital?You will be admitted to the hospital where your heart rate and rhythms will be monitored 24 hours a day throughout your stay. You will wear electrodes on your chest, which will be hooked up with wire leads to monitoring equipment If you are a male, first the nurse will shave the areas where the electrodes will be placed. On the day of the surgery, you will stop taking your medications What happens during the procedure?Usually the procedure is performed under local anesthesia, but sometimes it is done under general anesthesia. You will be hooked up to an intravenous (IV) line and will receive sedation. Before the physician makes an incision, the team will clean you and prepare a sterile environment. Your arms may be loosely strapped to prevent movement during the testing of the AICD. The physician will make an incision in your left pectoral region below the collar bone. A wire will be inserted through a big vein into your heart. Sometimes more than one wire is used. Tests of the equipment will be made. The physician will create a "pocket" in your chest, where he or she will insert the AICD. and then connect it to the wire or wires. The physician will test the AICD by creating an arrhythmia and then observing whether the AICD delivers the needed treatment. How long does the procedure take?The procedure usually takes about one hour. What happens after the operation?After the operation, you will be taken to a recovery room where you will remain for one or two hours. It's normal to feel pain. Do not hesitate to ask the nurse for pain medication. What happens after recovery?Later that day, or the next, your AICD system will be checked and tested again with a computer called a "programmer." This procedure is called "noninvasive programmed stimulation" or "predischarge testing." You will receive sedation. The doctor will provoke an arrhythmia to see if the device works. The AICD will deliver a shock (defibrillation).. The staff will fine tune the equipment. What happens at discharge?You will be shown how to examine your incision site. You should look for signs of infection each day: increased redness, increased tenderness, swelling around the incision, drainage from the incision. You should also report a fever of longer than 24 hours duration. You will receive instructions for the first few weeks following your discharge, as to exercising, bathing and walking. What will happen after my discharge?After a few weeks, you will return to the hospital for follow up.. At that time your chest will be inspected for bleeding or infections. The equipment will be tested again. You will continue to visit your doctor regularly, about every two or three months. What feelings should I expect to have?You have had a strong physical and emotional experience. Your feelings may go through similar stages to that of the grieving process: denial, sadness, anger, and finally acceptance. This is common. You may go through these feelings more than once and in a different order. That is normal, too. It is important to work through these feelings. Some hospitals have support groups. You can also talk with your clergy, nurse, doctor or a therapist. What about my family's feelings?Your spouse or family members may experience: fear, anxiety, anger, guilt, depression. They can benefit from support services, too. Will my lifestyle be affected by this implant?There will be a few changes in your life, some of them will be temporary. For example, your doctor will ask you not to drive your car for awhile. Expect a slow recovery. You may be aware of the AICD in the beginning, but you will adjust to it. You will gradually resume your normal lifestyle. This will include returning to your job, traveling, exercise, sexual activity, pursuing hobbies and recreational activities. You will receive an identification card for your wallet which has information about your AICD and emergency instructions. At the airport, you should not walk through the metal detector because your AICD's metal case may set off an alarm. Don't let anyone place a hand-held screening wand near your AICD because the repetitive motions of the wand may temporarily interfere with the proper operation of your implant. Present your identification card and request a hand search. You will have to avoid the following:
Common household appliances should not affect the AICD if they are used as. intended. These include: TV, computers, power hand tools and hair dryers and microwave ovens. It's a good idea to wear an ID bracelet or necklace which has information about your heart rhythms and your AICD. Tell your other doctors and dentist about your AICD. Keep ambulance or paramedic numbers close to the telephone. Consult your physician before buying over-the-counter medications. and before taking a trip, vacation or moving. Eventually, you will be able to lead an active lifestyle and may be able to do things you couldn't do before. |