An implantable cardioverter defibrillator (ICD) monitors your heart's activity and can treat heart rhythm problems, or arrhythmias, by delivering a jolt of electricity when it detects an irregular heartbeat. Studies have shown that those who have arrhythmias, and those who are at risk of having them, live longer with an ICD.
No, it won't. When something is cured, it's completely and permanently eliminated. An ICD is a treatment, not a cure. It acts instantly if your heart rhythm changes for the worse and treats the problem each time it occurs.
ICDs are most commonly used to treat arrhythmias. Many doctors combine an ICD with heart medications called antiarrhythmics. These medications keep the heart rhythm from getting too fast, and the ICD device protects you if your heart rate increases dangerously despite the medications.
In some cases, a heart rhythm disturbance can be cured with a procedure called catheter ablation. It is performed by an electrophysiologist (a cardiologist who specializes in arrhythmias).
No. Implantable cardioverter defibrillators can treat serious rhythm problems in the ventricles, the lower portions of the heart.
Often, good heart rhythm control can be achieved with medication alone. However, if your symptoms persist or worsen, or if the problem is potentially dangerous, your doctor may perform an electrophysiology (EP) study. An EP study provides more information about your heart's rhythm and the best treatments to deal with any issues. In some cases, the problem and its solutions are clear, and an EP study isn't necessary.
If an ICD is a potential treatment for your heart rhythm problem, your doctor will know and discuss it with you.
Implantable cardioverter defibrillators deliver electrical shocks at different strengths, depending on the patient's needs. Low-energy electrical charges don't hurt. You may not even notice them. High-energy charges can be painful, but they last less than a second. Some say that the high-energy shocks feel like being kicked in the chest.
Nothing will happen to them.
A shock from an implantable cardioverter defibrillator is less powerful than a shock given by paramedics or emergency room workers using paddles on the chest. Because the ICD shocks the heart directly, through wiring connected to the heart, it can achieve the same shock as external devices with far less energy. The energy that escapes to the surface, where someone might touch you, is completely harmless.
Once your doctor has said it's safe to do so, you can return to your regular activities, including work, school, driving, sex and exercise. How long it takes to get the doctor's clearance varies from person to person. It will depend on your particular situation and any other medical problems you have.
An ICD monitors your heart's rhythm and delivers a shock if it senses a dangerous rhythm. This treatment is called defibrillation. A pacemaker, on the other hand, uses electrical pulses to help the heart beat at a normal rate, thereby controlling abnormal heart rhythms. It can slow a fast heart rate, speed up a slow heart beat and more. Most new ICDs can act as both a defibrillator and a pacemaker.
When implantable cardioverter defibrillators were much larger, they were implanted in the abdomen. Now that they are smaller, doctors usually implant them in the chest, most often below the collarbone, on the right or left side of the chest. You may feel and see the outline of the device under the skin.
No. Implantable cardioverter defibrillator surgery is much simpler now than it was in the past. It often takes less than an hour.
For more information on the implant procedure, please see our treatment page on ICDs.
Implantable cardioverter defibrillators are battery powered. The type of battery used was chosen because it lasts for a long time, and the predictable way in which its power is gradually used. If an ICD delivers a large number of shocks, it will wear out sooner than one that rarely provides therapy.
Most ICDs last five years or more. Checking the battery is an important part of any evaluation of the device and doctors are careful to do this as part of their routine follow-up.
A normal clinic visit to the electrophysiologist or cardiologist usually includes inspecting your implantable cardioverter defibrillator. We use a piece of equipment, called a programmer, to check:
Long before the battery expires and the ICD's performance changes in any way, the doctor will know that it's time to plan for a replacement ICD.
At that point, we arrange a brief hospital stay – typically no more than two days – to allow the doctor to remove the old ICD and replace it with a fresh one. Replacement procedures are often simpler than original implantations, and take the doctor and patient even less time.
Some doctors prefer to see their implantable cardioverter defibrillator patients every two months or even more often when they feel the heart rhythm needs especially close observation. Others ask their patients to return every four to six months. This longer timeframe is more common among people whose rhythms are quite stable. You and your doctor will work out the right schedule for your situation.
Here’s what you should avoid with a defibrillator:
Interacting with these things could temporarily deactivate your ICD. This deactivation will persist as long as you are inside the electromagnetic field. The ICD will return to full function as soon as you move away from the magnetic field. In any case, your doctor doesn't want your device's operation suspended even briefly, so be sure to take the proper precautions.
You don't need to take any special precautions while using microwave ovens. Many years ago, some ICDs reacted badly in the presence of microwaves, but ICDs have since been modified and this is no longer the case.
UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.
