What is an implantable cardioverter-defibrillator?

Normally, an electrical signal in your heart starts each heartbeat, causing the heart muscle to squeeze (contract). This signal starts in the upper right chamber of the heart (the right atrium). The signal then follows normal pathways to the upper left atrium and to the lower chambers of the heart (the ventricles). When your heart cannot beat regularly because of a problem with the electrical signal or damage to your heart, you may need an ICD. Most ICDs can act as both a pacemaker and an ICD. ICDs can help heart conditions such as:

• Life-threatening heart rhythms, which may be caused by a heart attack, heart disease, or other health problems. An ICD can be life saving if you have a life-threatening heart rhythm or if your heart stops suddenly.
• A very slow, very fast, or irregular heart rhythm. A pacemaker can speed up a slow rhythm or control a very fast or irregular rhythm.
• Atrial fibrillation, which is a condition that causes the upper chambers of the heart (atria) to beat very fast and not in a normal pattern. A pacemaker can signal the lower chambers of your heart to beat if the upper chambers are not beating in a normal pattern.
• Heart failure, which means the heart is not pumping blood as well as it should. A pacemaker can help coordinate the electrical signals between the two lower chambers of your heart so that your heart pumps more effectively. This treatment is called cardiac resynchronization therapy (CRT). An ICD that can do cardiac resynchronization therapy is called CRT-D.

An implantable cardioverter defibrillator (ICD) is a small battery-powered device that helps your heart beat in a normal rhythm. The ICD device is placed under the skin in your chest or belly. You will be able to feel the device under your skin. It’s about the size of a large watch. The ICD is attached to wires that deliver electrical signals, or small electric shocks, to your heart. Your healthcare provider sets it to monitor your heart rhythm and send electrical signals to your heart, if needed. The electric signals cause your heart to beat in a regular pattern.

When your heart is beating normally, the ICD does nothing. If the ICD detects a heart rhythm that is too fast, too slow, or irregular, the device first tries to control the heart rhythm with low-level electric signals, like a pacemaker. If this doesn’t work, or the rhythm gets worse, the ICD sends a high-level shock to your heart. The electric shock changes the abnormal rhythm to a normal rhythm. You will feel the shock and it may be slightly painful.

Some devices can also monitor your blood temperature and breathing and adjust your heart rate when you are physically active.

How can I take care of myself when I go home?

How long it takes to get better depends on the cause of your irregular heart rhythm, how well you recover, your overall health, and any complications you may have.

Management

• Your provider will give you a list of your medicines when you leave the hospital.
  • Know your medicines. Know what they look like, how much you should take each time, how often you should take them, and why you take each one.
  • Take your medicines exactly as your provider tells you to.
  • Carry a list of your medicines in your wallet or purse. Include any nonprescription medicines and supplements on the list.
  • Talk to your provider before you use any other medicines, including nonprescription medicines. Some medicines and supplements can change your heart rate, which may affect how your ICD works.
• Ask your provider if you should take aspirin. Aspirin may help prevent blood clots that can cause a heart attack or stroke.
• Your provider may prescribe medicine to:
  • Treat pain
  • Treat or prevent an infection
  • Help prevent blood clots
  • Slow the heart rate and reduce the workload of the heart
  • Relax and widen blood vessels and allow blood to flow through them easier
  • Control cholesterol levels
  • Reduce fluid build-up and swelling in the body
• To care for your ICD insertion site:
  • Keep your incision clean.
  • If you are told to change the dressing on your incision, wash your hands before changing the dressing and after disposing of the dressing.

Appointments

• Follow your provider’s instructions for follow-up appointments and routine tests.
• You will need regular follow-up visits with your healthcare provider so the device can be monitored. At your follow-up visit, your provider will check your ICD settings, the battery, and your heart. The batteries last about 6 to 10 years. When your battery runs down, you will need minor surgery to replace the device.
• You will learn how to check the function of the ICD at home and send information to your healthcare provider through a telephone.
• Keep appointments for all routine testing you may need.
• Talk with your provider about any questions or fears you have.

Diet, Exercise, and Other Lifestyle Changes

• Follow the treatment plan your healthcare provider prescribes.
• Get plenty of rest while you’re recovering. Try to get at least 7 to 9 hours of sleep each night.
• Eat a healthy diet.
• Drink enough fluids to keep your urine light yellow in color, unless you are told to limit fluids.
• Exercise as your provider recommends.
• Don’t smoke. Smoking can worsen poor blood circulation.
• Lose weight if you need to and keep a healthy weight.
• Find ways to make your life less stressful.
• Follow activity restrictions, such as not driving or operating machinery, as recommended by your healthcare provider or pharmacist, especially if you are taking pain medicines or muscle relaxants.
• You will need to avoid equipment that may interfere with your ICD. For example, you will need to keep cell phones and other mobile devices at least 6 inches away from your device and avoiding power-generating equipment, arc-welding equipment. Equipment that generally will not interfere with your ICD includes radios, electric drills, heating pads, electric shavers, microwave ovens, and televisions.
• Tell all of your healthcare providers and dentists that you have an ICD. Some tests and treatments can interfere with your ICD, such as magnetic resonance imaging, radiation treatment for cancer, deep heat treatment, and shock wave treatment to dissolve kidney stones. Your ICD may need a different set-up if you need one of these treatments, or your provider may recommend different tests or treatments.

Call emergency medical services or 911 if you have new or worsening:

• Chest pain or pressure, squeezing, or fullness in the center of your chest that lasts more than a few minutes, or goes away and comes back (may feel like indigestion or heartburn)
• Pain or discomfort in one or both arms or shoulders, or in your back, neck, jaw, or stomach
• Trouble breathing
• Breaking out in a cold sweat for no known reason
• Along with the previous symptoms, feeling very tired, faint, or sick to your stomach
• Weakness, numbness, tingling or pain in your face, arm, or leg, especially on one side of your body

Do not drive yourself if you have any of these symptoms.

Call your healthcare provider if you have new or worsening:

• Feeling like your heart is beating too fast, too slow, or skipping beats
• Numbness in your arm or hand on the same side as the pacemaker insertion site
• Signs of infection around your surgical wound. These include:
  • The area around your wound is more red or painful
  • Your wound area is very warm to touch
  • You have blood, pus, or other fluid coming from the wound area
  • You have a fever higher than 101.5° F (38.6° C)
  • You have chills or muscle aches

Ask your healthcare provider about any medicine, treatment, or information that you do not understand.