Subcutaneous Implantable Cardioverter Defibrillator (S-ICD)


What is a subcutaneous implantable cardioverter defibrillator (S-ICD)?

A subcutaneous implantable cardioverter defibrillator (S-ICD) is a type of implantable cardioverter defibrillator (ICD). An ICD is an electronic medical device that helps prevent sudden cardiac death. The subcutaneous version of the device goes under your skin.

Healthcare providers recommend ICDs for people with certain cardiac conditions to monitor heart rhythm. When the device detects a very fast, abnormal heart rhythm, it delivers a shock to your chest to reset your heart rhythm. This is defibrillation.

What is the difference between ICD and S-ICD?

Traditional ICDs use one to three wires (leads) that run through veins to your heart. This is a transvenous approach (TV-ICD). But subcutaneous ICDs are less invasive because they use only one lead that runs under your skin, not through your veins. This can reduce the risk of complications and make it easier to replace or remove leads.

Who needs to have a subcutaneous ICD?

ICDs are often used in people who have heart conditions such as:

An S-ICD may be the best ICD option in people who:

  • Are at risk for infections or have had prior ICD infections.
  • Have cardiac anatomy that is difficult to access.
  • Live very active lifestyles.
  • Are younger and likely to live longer than transvenous ICDs usually last.

Can a subcutaneous ICD pace?

Some ICDs also act as pacemakers, which help regulate and maintain normal heart rate and rhythm. As of 2022, S-ICDs do not have the ability to pace. Therefore, they can't help your heart maintain a normal rate or rhythm. They can only monitor your heart and shock it out of an abnormal heart rhythm if needed.

Procedure Details

What happens before the subcutaneous implantable cardioverter defibrillator procedure?

Your healthcare provider will give you specific instructions before the S-ICD procedure. They may ask you to:

  • Stop taking certain medications, such as blood thinners, a few days before the procedure.
  • Avoid food and water the day of the procedure.
  • Arrange for a ride home after the procedure.

Just before the procedure, a healthcare provider may:

  • Mark anatomical locations for incisions and device placement.
  • Shave and clean the area where your surgeon will implant the device.
  • Insert an IV line into your arm to deliver medications and fluids.
  • Administer antibiotics to prevent infections.
  • Administer anesthesia to prevent pain.
  • Use a soft strap to hold your arms in place and prevent you from touching the sterile area.

What happens during this procedure?

The procedure to implant an S-ICD usually takes a couple of hours. It requires inserting two parts: a generator and a defibrillation lead.

Most people receive conscious sedation and are awake but relaxed during the procedure. You should not feel any pain, so tell your healthcare provider if you do.

During the procedure, your healthcare provider continuously monitors your vital signs and the progress of the procedure, often using:

A surgeon will make two or three incisions on the left side of your chest or under your left arm. They insert the generator next to your rib cage, under your skin and inside fat. Then they tunnel the lead under your skin to the middle of your chest near your breastbone, then up toward your neck.

Before finishing the procedure, they test the system by inducing an abnormal heart rhythm and allowing the device to shock you to prove that it’s working properly. (Your medical team will keep you under sedation with medications to ensure you don’t feel any pain.) Then they use stitches to close the incisions.

What happens after S-ICD surgery?

After the procedure, you go to a recovery room. There, the healthcare team monitors you as the anesthesia wears off. Your healthcare provider may order an X-ray to check the position of the device components.

Most people go home the day of the procedure. Because of the anesthesia, you'll need someone to drive you home.

Risks / Benefits

What are the advantages of a subcutaneous defibrillator?

An S-ICD can prevent sudden cardiac death and lower the risks associated with transvenous ICD, such as:

  • Cardiac perforation (tear in your heart tissue).
  • Infections, including endocarditis.
  • Problems with leads breaking, which need replacement or removal.
  • Thrombosis or blood clots.

What are the risks or complications of a subcutaneous ICD implant?

Implantation of an S-ICD involves the risk of complications, although rare. They include:

  • Bleeding.
  • Blood clots.
  • Damage to nearby tissues (for example, tendons, muscles, nerves).
  • Infection of the incision.

Other risks over time may include:

  • Erosion of your skin near the device.
  • Device movement from the original implant site.
  • Irritation from the leads.
  • Unnecessary shocks from the device.

Recovery and Outlook

How do I take care of myself with an S-ICD implant?

Your healthcare provider will give you specific instructions about living with an S-ICD. They may include:

  • Attend regular follow-up appointments to check your heart health and the device’s functionality.
  • Carry a card or wear a bracelet that identifies you as someone with an ICD. This can be especially helpful for emergency medical personnel.
  • Inform all other healthcare providers that you have an S-ICD.
  • Talk to your doctor before you travel, particularly if you’ll have to go through security machines such as metal detectors.

How long does an S-ICD last?

You can’t recharge an S-ICD’s battery because it’s sealed within the device. When the battery depletes, a surgeon will have to remove and replace the device.

On average, an S-ICD battery lasts almost five years. Battery life depends on several factors, including its settings and how often the device activates. Your healthcare provider will check battery life at follow-up appointments.

When to Call the Doctor

When should I seek medical attention after getting an S-ICD?

If you experience signs of infection or heart trouble after S-ICD implantation, seek medical attention. Signs may include:

  • Chest pain.
  • Dizziness.
  • Drainage of fluid or pus from the incision site.
  • No resolution of the cardiac symptoms you had before S-ICD implantation.
  • Redness, swelling or pain near an incision.
  • Shortness of breath.

A note from Cleveland Clinic

A subcutaneous implantable cardioverter defibrillator (S-ICD) is a medical device implanted under your skin. It can help prevent sudden cardiac death in people with certain heart conditions who meet other criteria. If you need an implanted defibrillator, ask your healthcare provider if an S-ICD is right for you.

Last reviewed by a Cleveland Clinic medical professional on 08/05/2022.


  • European Society of Cardiology. The subcutaneous defibrillator: who stands to benefit. ( Accessed 8/5/2022.
  • Kamp NJ, Al-Khatib SM. The subcutaneous implantable cardioverter-defibrillator in review. ( Am Heart J. 2019;217:131-9. Accessed 8/5/2022.
  • Kaya E, Rassaf T, Wakili R. Subcutaneous ICD: Current standards and future perspective. ( IJC Heart & Vasculature. 2019; 24:100409. Accessed 8/5/2022.

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