Implantable Cardioverter Defibrillators (ICDs)

An Implantable Cardioverter Defibrillators (ICDs) is a device that intervenes in arrhythmias where the heart beats dangerously fast, such as ventricular tachycardia and ventricular fibrillation, by giving a shock to the heart and correcting its rhythm. It is usually placed under the skin in the upper part of the chest, just below the collarbone. ICD is especially designed for patients at high risk of sudden cardiac arrest and can significantly extend life span and improve quality of life.

What is an implantable cardioverter defibrillator?

An implantable cardioverter defibrillator (ICD) is a small, battery-powered device that is surgically placed under the collarbone to correct abnormally fast heart rhythms. This device connects to your heart through one or more wires (electrodes). These wires continuously monitor the electrical activity in your heart and provide a gentle stimulation or a strong shock if necessary to correct heart rhythm when an abnormal rhythm is detected.

How does an ICD work?

An ICD monitors the electrical activity in your heart at all times and intervenes when it detects an abnormal rhythm. When the device detects that your heart is beating too fast or irregularly, it first tries to correct the rhythm by sending gentle electrical stimulations. If these stimulations don’t work, it provides a shock to restore your heart’s normal beating.

An ICD can work in different modes:

• The ICD monitors your heart’s electrical activity 24/7. When it detects a normal heart rhythm, it does not intervene.
• When your heart beats very fast but regularly (such as ventricular tachycardia), the ICD sends very small and imperceptible electrical stimulations. These stimulations stop the fast rhythm and help your heart return to normal rhythm. Most patients don’t feel this intervention.
• When it detects that your heart is beating very fast and chaotically (ventricular fibrillation), the ICD sends a strong electrical shock. This shock resets all electrical activity in your heart, creating an opportunity for it to return to normal rhythm. This shock is usually described as feeling like a kick or punch to the chest.

What are the types of ICDs?

ICDs come in different types according to their placement method and functions. Your doctor selects the most suitable ICD model for you according to the type of your heart disease and your needs.

The main ICD types are:

• Single-Chamber ICD: Monitors and treats only one chamber of your heart (usually the right ventricle) through a single wire.
• Dual-Chamber ICD: Monitors both chambers with two wires placed in both your right atrium and right ventricle. This allows more detailed monitoring of the source of arrhythmias.
• Subcutaneous (S) ICD: Placed under the skin on the left side of the breastbone and works without wires extending to the heart. This is a less invasive option for some patients as it doesn’t require placing wires inside the heart.
• Cardiac Resynchronization Therapy (CRT)-D: Designed for some patients with heart failure. It helps both reduce heart failure symptoms and prevent dangerous arrhythmias.

Why is an ICD implanted?

An ICD is implanted to protect the lives of patients at high risk of sudden cardiac arrest. This device detects risky arrhythmias and intervenes in time, significantly reducing the risk of sudden death.

The main reasons for ICD implantation are:

• In patients who have had a previous heart attack and whose heart’s pumping power (ejection fraction) has significantly decreased, the risk of sudden cardiac arrest increases.
• It is implanted to provide protection in patients diagnosed with ventricular fibrillation or ventricular tachycardia.
• Cardiomyopathy is a disease of the heart muscle. ICD implantation is recommended in this condition that leads to heart failure and increases the risk of dangerous arrhythmias.
• It is applied for protection in people with genetic heart diseases such as Brugada syndrome or long QT syndrome who therefore carry the risk of sudden death.
• In patients with advanced heart failure, it can be implanted both to prevent arrhythmias and to support the heart’s pumping function.

Preparation before ICD procedure

Before ICD implantation, ECG, echocardiography, and blood tests are performed to evaluate your heart rhythm, functions, and general health condition. The medications you use may be discontinued before the procedure. You will be informed about eating and drinking. Your doctor will provide information on these topics.

How is an ICD implanted?

ICD implantation is a procedure performed in a sterile operating room environment, usually under local anesthesia and light sedation. This procedure usually resembles a pacemaker implantation procedure and takes an average of 1-2 hours.

A small incision is made just below your collarbone and a “pocket” is created where the device will be placed. Special wires (electrodes) are placed in your heart’s chambers through a large vein in your chest. The wires are connected to the ICD generator. After the device is implanted, your doctor performs a short test to check that the device is working correctly. During this test, a mild arrhythmia is triggered to check whether the ICD gives a shock. The device is placed in the pocket and the incision site is closed with stitches.

What do you feel after ICD implantation?

It is normal to feel mild pain and discomfort in the first days after ICD implantation. Except for the moment of shock delivery, you usually don’t feel the presence of the device. ICD shock delivery is usually described as an unexpected hard kick or punch feeling to the chest. This feeling lasts for a few seconds. The situations where the device accelerates your heart (pacing) are usually not felt.

Living with an ICD and what to pay attention to

After ICD implantation, most patients can return to normal life, but you need to take some precautions to ensure the device works smoothly.

What you need to pay attention to when living with an ICD:

• You should go to regular doctor check-ups to control the device’s battery life and functionality.
• You should stay away from devices with strong electromagnetic fields (for example, strong magnets, industrial welding machines). Carry your cell phone on the opposite side of the pocket where your device is located.
• You can do light and moderate exercise with your doctor’s approval, but you should avoid sports where you could receive blows to your chest, such as contact sports.
• At airports, you need to inform security personnel that you have a device and show your ICD identification card.
• If you feel that you have received a shock from your ICD, you should immediately consult your doctor or emergency room.

What are the risks of ICD?

ICD implantation is generally a safe procedure, but like any surgical procedure, it carries some risks. These risks are usually low.

Risks related to ICD implantation procedure are:

• Infection may occur in the area where the device is placed.
• Bleeding may occur during or after the procedure.
• Rarely, the pleura may be punctured and lung collapse may occur.
• Rarely, the device or wires may malfunction.
• The device may perceive a non-dangerous arrhythmia as dangerous and give an unnecessary shock. This is called inappropriate shock.

When should you consult a doctor?

If you experience any problems after ICD implantation or have concerns about the device, you should consult your doctor without delay.

Emergency medical evaluation is required in the following situations:

• If you feel your ICD has given a shock
• If you see signs of infection such as redness, swelling, increased temperature, or discharge in the procedure area
• If symptoms such as fainting, dizziness, or palpitations recur
• If your fever rises or you don’t feel well

Referans: ICD