Getting diagnosed with hypertrophic cardiomyopathy (HCM) can feel confusing and overwhelming, especially when you’re discussing treatment options. For some people with HCM, an implantable cardioverter defibrillator (ICD) can improve quality of life and may even be lifesaving. However, the idea of having a device implanted can bring up many questions and concerns.

Below, we’ll explain what ICDs are, how they work, and why you might be a candidate for one. We’ll also share tips for living with an ICD after your procedure.

ICDs are small, battery-powered devices placed in the chest that continuously monitor for irregular heart rhythms. If a dangerous rhythm is detected, the device delivers an electrical shock to restore a normal heartbeat.

An ICD includes a pulse generator and one or more thin wires called leads. The pulse generator contains a battery and electrical circuits that monitor the heart’s electrical activity.

The three main types of ICDs differ in where they’re placed and which functions they provide.

Transvenous ICDs

Transvenous implantable cardioverter defibrillators (also called traditional ICDs) connect the pulse generator to the heart using leads threaded through the veins. The leads connect to specific areas inside the heart.

The pulse generator is implanted below the collarbone and is roughly the size of a small matchbox.

Traditional ICDs are the standard treatment for people who have experienced or are at high risk of cardiac arrest (when the heart stops beating). Many traditional ICDs can also work as pacemakers or help the heart pump more effectively through cardiac resynchronization therapy.

Subcutaneous ICDs

Subcutaneous implantable cardioverter defibrillators (S-ICDs) use a single lead (also called an electrode) placed under the skin along the breastbone. Unlike traditional ICDs, an S-ICD’s lead doesn’t pass through the veins or touch the heart.

Pulse generators for S-ICDs are larger than those used with traditional ICDs and are placed under the skin near the left armpit.

An S-ICD can’t work as a pacemaker or provide cardiac resynchronization therapy.

Extravascular ICDs

Extravascular implantable cardioverter defibrillators (EV-ICDs) are a newer type of ICD. EV-ICDs use a single lead that’s placed under the breastbone near the heart, not in the veins.

The pulse generator is placed under the skin near the left armpit. These devices are smaller than other ICDs.

EV-ICDs can treat rapid heartbeats and temporarily control a slow heartbeat, but they can’t provide cardiac resynchronization therapy or long-term pacemaker support.

HCM can cause arrhythmias (irregular heart rhythms). Some of the arrhythmias that affect the ventricles (the heart’s lower chambers) are especially dangerous, including ventricular tachycardia (VT) and ventricular fibrillation (VF). Both VT and VF can lead to cardiac arrest.

An ICD constantly monitors for irregular heart rhythms. If the device detects a life-threatening rhythm, it delivers a shock to restore a normal heartbeat.

An ICD constantly monitors for irregular rhythms. If the device detects a life-threatening heart rhythm, it delivers a shock to restore a normal heartbeat. In this way, ICDs can help prevent sudden cardiac death.

If your device has these features, an ICD can also deliver lower-energy pulses to treat fast heart rhythms. Called overdrive pacing, this is usually less painful than a defibrillation shock. ICDs can also treat slow heart rhythms with backup pacing.

Your healthcare team will program the device based on your specific heart rhythm needs.

You may benefit from an ICD if you have risk factors for sudden cardiac arrest, including:

• A family history of sudden cardiac arrest
• A history of ventricular arrhythmias
• Severe thickening of the heart muscle
• Unexplained fainting
• Reduced heart function

To determine if you’re a good candidate for an ICD, your doctor will review your risk factors and the results of tests such as:

• Electrocardiogram (ECG)
• Cardiac MRI
• Echocardiogram
• Holter monitor or event recorder

People with HCM may benefit from an ICD if they have risk factors for sudden cardiac arrest.

Deciding whether to get an ICD is an important personal decision. Talk with your doctor about the risks and benefits, along with your own personal preferences and treatment goals.

Getting an ICD involves a minor surgery performed by a cardiologist who specializes in the heart’s electrical system. ICD implantation procedures can vary, but most take two to three hours and are done using either local anesthesia (which numbs the area) or general anesthesia (which puts you to sleep).

Your healthcare provider will give you instructions on how to prepare for the procedure. You may need to stop certain medications and avoid food and drinks for several hours before the surgery.

During an ICD procedure, the doctor makes a small incision where the device will be placed. The leads are then guided into place. Next, the doctor places the pulse generator and connects the leads.

Getting an ICD involves a minor surgery performed by a cardiologist who specializes in the heart’s electrical system.

After everything is in place, the doctor tests the ICD to make sure it’s working properly. Depending on the procedure, you may go home the same day or stay overnight in the hospital.

After the Procedure

The area where the ICD is implanted may feel sore and look swollen for a few days or weeks. Your doctor may advise you to avoid strenuous activities, such as exercise, sports, or heavy lifting, for several weeks after surgery. It’s also important to avoid lifting your left arm above your shoulder, because this can move the leads before the area has healed.

The pulse generators in all types of ICDs will eventually need to be replaced because the batteries wear out over time. Battery life depends on the type of ICD:

• Traditional ICDs — Batteries usually last about seven years, but this can vary from person to person.
• S-ICDs — Batteries generally don’t last as long as those in traditional ICDs.
• EV-ICDs — Batteries may last up to 12 years.

Problems with the leads are more common with traditional ICDs than with S-ICDs. One study found that lead failure, dislodgement (lead movement), and infections that required ICD removal or additional surgery were more common with traditional ICDs than with S-ICDs.

After getting an ICD, it’s important to understand how the device works and follow your doctor’s instructions. Your healthcare team will check the device several times a year to make sure it’s functioning properly.

Here are some factors to keep in mind as you adjust to living with an ICD.

Physical Activity

You should be able to return to most daily activities shortly after surgery. Staying physically active can help improve circulation and overall heart health.

However, you may need to wait about a month before lifting heavy items or doing strenuous activities. Talk with your doctor before returning to sports or intense exercise.

Interference From Machines

Machines that use strong magnets or electrical fields can interfere with your ICD. These include anti-theft systems in stores, airport metal detectors, and some household electronics, such as cellphones, headphones, and radios.

For a complete list of devices to avoid or limit, review the American Heart Association’s recommendations on devices that may interfere with ICDs and pacemakers.

Interactions With Medical Procedures

Some medical procedures and tests can interfere with an ICD. Be sure to tell all healthcare providers, technicians, and dentists that you have an ICD.

It’s also a good idea to carry an ICD identification card in your wallet in case of an emergency. Some people also choose to wear a medical alert bracelet or necklace.

Travel Considerations

In general, traveling by car, plane, or train should not interfere with your ICD. However, it’s important to tell airport security screeners or other security staff that you have the device.

Ask your doctor when it’s safe for you to drive after ICD implantation surgery. If you’ve experienced fainting or sudden cardiac arrest, you may have to wait up to six months before driving again.

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