Implantable cardioverter defibrillator (ICD)


An implantable cardioverter defibrillator (ICD) is a compact, battery-powered device that is surgically implanted into the chest. Its primary function is to detect and correct irregular heart rhythms, known as arrhythmias. The ICD continually monitors the heart’s rhythm and administers electrical shocks when necessary to restore a normal heartbeat.

Individuals may require an ICD if they experience life-threatening rapid heart rhythms like ventricular tachycardia or ventricular fibrillation. Additionally, an ICD might be recommended for those with a heightened risk of dangerous arrhythmias, typically due to a weakened heart muscle.

It’s important to note that an ICD differs from a pacemaker, which is designed to prevent excessively slow heartbeats.


Cardiac therapy devices include devices like ICDs. Two basic types include the following: (1 all)

  • Traditional ICD: This type is surgically placed in the chest, with wires called leads connecting it to the heart.
  • Subcutaneous ICD (S-ICD): The S-ICD is implanted beneath the skin, typically on the side of the chest below the armpit. It is connected to a sensor called an electrode, which runs alongside the breastbone. The S-ICD is larger in size compared to a traditional ICD and does not make direct contact with the heart.

Reasons for undergoing the procedure

An implantable cardioverter-defibrillator (ICD) is a medical device designed to continuously monitor and promptly correct irregular heart rhythms. It is particularly beneficial in cases of sudden and complete loss of heart activity, a condition known as cardiac arrest.

ICDs serve as the primary treatment option for individuals who have survived cardiac arrest. Furthermore, they are increasingly being employed in individuals at a high risk of experiencing sudden cardiac arrest. An ICD significantly reduces the risk of sudden death from cardiac arrest compared to relying solely on medication.

If you exhibit symptoms of a sustained irregular heart rhythm called sustained ventricular tachycardia, such as fainting, your cardiologist may recommend the implantation of an ICD. Additionally, an ICD might be advised if you have:

  • Brugada syndrome.
  • Specific forms of congenital heart disease.
  • Hypertrophic cardiomyopathy.
  • Long QT syndrome.
  • A history of a previous sudden heart attack (myocardial infarction) or cardiac arrest.
  • Ventricular arrhythmia.
  • Ventricular fibrillation.


Potential complications associated with implantable cardiac defibrillators (ICDs) or the surgical procedure for implantation can include:

  • Swelling, bleeding, or bruising.
  • Infection at the site of implantation.
  • Damage to blood vessels from ICD wires.
  • Potentially life-threatening bleeding around the heart.
  • Occurrence of a collapsed lung.
  • Leakage of blood through the heart valve near the ICD lead.
  • Device or lead migration, possibly resulting in damage to the heart muscle; a rare complication known as cardiac perforation.

Before the procedure

Prior to receiving an implantable cardiac defibrillator (ICD), a series of heart health assessments are typically conducted. These assessments may include:

  • Electrocardiogram (ECG or EKG): An ECG is a painless test that examines the heart’s rhythm. It involves placing adhesive electrodes on the chest (sometimes on the arms and legs as well) connected to a computer, which displays or prints the heart’s electrical activity. An ECG can detect irregular heartbeats, whether too fast or too slow.
  • Echocardiogram: This imaging test utilizes sound waves to produce dynamic images of the heart, revealing its size, structure, and blood flow patterns.
  • Holter monitoring: A Holter monitor is a small wearable device that continuously tracks heart rhythm over 1 to 2 days. It can identify irregular heart rhythms that may not be captured during a standard ECG. Sensors attached to the chest are connected to a battery-operated recording device, which can be carried in a pocket or worn on a belt or shoulder strap. Patients may be asked to record their activities and symptoms during the monitoring period for comparison with device data.
  • Event monitor: This portable ECG device is worn for an extended period, often up to 30 days or until an arrhythmia or symptoms are experienced. Patients typically press a button when symptoms occur.
  • Electrophysiology study (EP Study): An EP study may be performed to confirm a diagnosis of rapid heartbeat (arrhythmia) and locate the specific area in the heart responsible for irregular heartbeats. During this procedure, a flexible tube (catheter) is guided through a blood vessel into the heart, often using multiple catheters with sensors on their tips to record the heart’s electrical signals.

Before the ICD procedure, patients are generally instructed not to eat or drink for several hours.

It is important to inform your healthcare team about all medications you are taking and inquire whether it is advisable to take them before the ICD procedure.

During the procedure

Getting an implantable cardioverter defibrillator (ICD) involves a few important steps:

  • Preparation: A member of your healthcare team will insert an IV into your forearm or hand to administer any necessary medications, such as sedatives, to help you relax. Electrodes are placed on your chest and sometimes on your legs to monitor your heart throughout the procedure.
  • Anesthesia: Depending on your specific needs, you may either be awake with mild sedation or under general anesthesia, which puts you in a sleep-like state. Your healthcare team will discuss the type of sedation that’s best for you.
  • Insertion: To place the ICD, a small incision is made in the chest area. One or more flexible wires, known as leads, are carefully inserted into a blood vessel near the collarbone. These leads are guided to the heart, with one end attaching to the heart itself and the other end connecting to a device called a shock generator, which is implanted under the skin beneath the collarbone.
  • Procedure duration: The entire procedure to implant the ICD typically takes a few hours.
  • Testing and programming: Once the ICD is in place, your doctor tests and programs it to suit your specific heart rhythm needs. This may involve speeding up your heart temporarily and then using the ICD to restore a regular rhythm.
  • ICD settings: Depending on your heart condition, the ICD can be programmed for different functions:
    • Low-energy pacing: This setting responds to mild changes in your heartbeat and is usually painless.
    • Higher energy shock: For more serious heart rhythm issues, the ICD may deliver a stronger shock, which can be momentarily painful but typically doesn’t cause lasting discomfort.

    Usually, only one shock is required to restore a regular heartbeat. Some individuals may experience two or more shocks within a 24-hour period.

  • Electrical storm: If you experience three or more shocks in a short period, it’s called an electrical or arrhythmia storm. In such cases, it’s crucial to call 911 or seek emergency medical help. Your healthcare team will assess whether your ICD is functioning correctly or if you’re experiencing irregular heartbeats.
  • Adjustment: If necessary, the ICD can be reprogrammed to reduce the frequency of shocks. Additionally, medications may be prescribed to help control your heartbeat and decrease the risk of experiencing an ICD electrical storm.

After the procedure

After your ICD procedure, you’ll typically head home the following day. During the recovery period, you might experience swelling and tenderness around the ICD placement site for a few days or weeks. Your doctor may prescribe pain medication for relief, but remember to avoid aspirin and ibuprofen, as they can increase the risk of bleeding.

For approximately eight weeks post-ICD implantation, it’s important to refrain from sudden movements that raise your left arm above your shoulder. This precaution helps prevent the device wires from shifting while the area heals. Depending on the type of ICD you received, you may need to limit your driving. Your healthcare team will provide specific guidance on when it’s safe to resume driving and other daily activities.

During the first four weeks following the ICD implant, your healthcare team may advise against the following activities:

  • Engaging in energetic sports or activities that involve lifting your left arm above your shoulder, such as golf, tennis, swimming, bowling, or vacuuming.
  • Avoid heavy lifting.
  • Steer clear of other strenuous forms of exercise.

Additionally, your doctor may recommend avoiding contact sports altogether after getting an ICD. A blow to the chest area could potentially damage the ICD or displace its wires.

ICDs (Implantable Cardioverter Defibrillators) are generally safe, but there are some precautions to consider:

  • Cellular phones: Keep your cellphone at least 6 inches away from your ICD to prevent interference.
  • Security systems: Show your ICD card to airport security as it may trigger alarms.
  • Metal detectors: Avoid scanning your ICD for more than 30 seconds at security checkpoints; request a manual search at airports if necessary.
  • Medical equipment: Inform your healthcare team about your ICD, as MRI and certain treatments may need alternatives.
  • Power generators: Stay 2 feet away from welding equipment and high-voltage transformers.
  • Headphones and wireless chargers: Keep these devices at least 6 inches away from your ICD.
  • Magnets: Maintain a 6-inch distance between magnets and your ICD.

Devices with low or no risk include microwave ovens, TVs, remote controls, radios, toasters, electric blankets, shavers, drills, computers, scanners, printers, and GPS devices.

Driving Restrictions:

  • If you have an ICD for ventricular arrhythmia, you may have driving restrictions due to the risk of fainting.
  • Some countries impose driving restrictions for ICD recipients.
  • If you receive a shock from your ICD, notify your healthcare team and avoid driving until you’ve been shock-free for several months.
  • If you have an ICD without a history of life-threatening irregular heartbeats, you can often return to driving about a week after implantation, but consult your healthcare team for specific guidance.
  • Commercial driver’s licenses are usually not granted to ICD recipients.


Patients who receive an ICD must schedule routine check-ups to have the device and their heart checked.

An ICD’s lithium battery has a five-to seven-year lifespan. Typically, routine medical check-ups, which should take place roughly every six months, involve a battery check. Find out how frequently they should get checked out by asking the healthcare provider. A brief outpatient surgery is performed to replace the generator when the battery is almost dead.

Any shocks the patient receives from their ICD should be reported to the healthcare provider. The shocks may give anyone an anxious feeling. However, what they really mean is that the ICD prevents sudden death and treats a cardiac rhythm issue.

Inform the patient’s healthcare provider if they have any infection-related symptoms following ICD implantation surgery:

  • Bleeding
  • Fever
  • Chills
  • Fluid discharge like pus that is coming from the incision site.
  • Pain that only worsen.
  • Swelling and redness

It is important to seek immediate medical attention if the patient experienced severe shocks for only a short period of time after ICD surgery.