An implantable cardioverter-defibrillator or ICD is a device that's connected to your heart.

It helps protect you from dangerous heart problems by working to keep your heart beating safely.

If needed, the ICD can give a shock to your heart that may save your life.

The ICD is placed under the skin of your chest.

It's attached to one or more wires, called leads.

For some types of ICDs, one or two leads are threaded through a large blood vessel and into the heart.

For another type, a lead is placed under the skin so it lies near the heart.

Here's how an ICD works.

It's always checking your heart rate and rhythm.

Depending on the type of ICD, if it detects a dangerous rapid heart rhythm, it may use electrical pulses to try to bring the rhythm back to normal.

If the dangerous rhythm doesn't stop, the ICD will send a life-saving electric shock to help restore the rhythm.

Now the shock may hurt for a short time.

Some people say it feels like a punch in the chest.

But although it may hurt, that shock means that your ICD is doing its job and may even be saving your life.

When you get your ICD, you and your doctor will have a plan in place, so you'll know exactly what to do if you get a shock from your ICD.

But even with a plan, many people feel anxious about having an ICD and worry about getting a shock.

If you're concerned or scared, be sure to talk to your doctor.

It can help to remember that with an ICD, you can still do the things you enjoy.

It's possible to live a healthy, active life when you have an ICD, because no matter what you're doing, it's always there working to protect your heart.