An implantable loop recorder (ILR) is a heart recording device. It's implanted in the body under the chest skin. It has several uses. The most common ones include looking for causes of fainting, palpitations, very fast or slow heartbeats, and hidden rhythms that can cause strokes. Loop recorder implantation is considered a minor procedure. For the procedure, your heart doctor (cardiologist) places the small device under your skin, in your chest wall, overlying the heart. The machine works as an electrocardiogram (ECG). It constantly picks up electrical signals from your heart and records anything abnormal. This can help identify heart rhythms that can cause problems, such as fainting.

Normally, a special group of cells initiate the electrical signal to start your heartbeat. These cells are in the sinoatrial node. This node is in the upper right chamber of your heart (right atrium). The signal quickly travels down your heart's conducting system to the ventricles. These are the two lower chambers of your heart. As it travels, the signal sets off nearby parts of your heart to contract. This helps your heart pump blood in a coordinated way.

Any disruptions to this signaling pathway may result in heart rhythm problems. These might cause problems, such as fainting and palpitations. An abnormal heart rhythm (arrhythmia) may make your heart unable to pump as much blood as needed. If blood flow to your brain is reduced for a short time, you may faint. When the rhythm returns to normal, blood flow is restored and you normally regain consciousness.

An implantable loop recorder constantly records information about your electrical activity, similar to an ECG. But an ILR can record heart rhythm for up to 3 years. This is particularly useful if your arrhythmia doesn't occur often. An ILR is constantly looping its memory. And it has automatic triggers to store recordings. It can also be patient-activated to store recordings as well. If you fainted due to an arrhythmia, the machine records this information before, during, and after the fainting. Then a doctor can look at the recordings to figure out the cause. Most current ILRs have a home monitor that can send data to your doctor.

You might need an ILR if you have fainting episodes or palpitations, and other tests haven't yet given you any answers. Each heart rhythm problem may need its own treatment. It's important to find out what kind of problem you may have, if any. Repeated fainting can have a negative effect on your physical and emotional health. Also some kinds of fainting greatly increase your chance for sudden death. These fainting episodes need diagnosis and treatment as soon as possible. Once you're diagnosed, you may need a pacemaker or an implantable cardioverter-defibrillator. These could save your life. You might also need a loop recorder if your doctor wants to look for very fast or slow heartbeats. These abnormal heartbeats can cause palpitations or even lead to strokes.

Loop recorder implantation is often helpful if other tests haven't found the cause. Your doctor is more likely to advise it if your heart rhythm is a likely cause of your fainting. This is more common in older adults. It's also more common in people with other heart problems. You're also more likely to need loop recorder implantation if you are fainting often, but not enough for other kinds of heart rhythm monitoring to find your fainting. The loop recorder records for up to 3 years. So over time your doctor should be able to analyze your heart rhythms during a fainting episode.

You also might need a loop recorder if you're an older adult with unexplained falls. Or if you've had a stroke without a clear reason. Sometimes arrhythmias are responsible for these conditions. Doctors sometimes use it in people believed to have epilepsy who haven't responded to medicine. In each case, the recorder can figure out if an abnormal rhythm is the problem.

Most people have the procedure without any problems. But sometimes problems happen. These might include:

• Bleeding or bruising
• Infection (might require device removal)
• Mild pain at your implantation site

Your own risks will depend on your age, your other health conditions, and other factors. Ask your doctor about any risks of the procedure for you.

Talk with your doctor about what you should do to get ready for your procedure. Follow any directions you're given for not eating or drinking before your procedure. Follow your doctor's instructions about what medicines to take before the procedure. Don't stop taking any medicine unless your doctor tells you to do so. You might also need tests before the procedure, such as an ECG.

Ask your doctor about what to expect during your procedure. Normally, you can expect the following:

• A local anesthetic will be put on your skin to numb it.
• Your doctor will make a small cut (incision) in your skin. This is often done in the left upper chest.
• Your doctor will then inject the device through the cut under the skin. The machine is about the size of a flat AAA battery.
• Your cut will be closed with glue, stitches, or possibly staples. A bandage will be put on the area.

Ask your doctor about what to expect after your procedure. In most cases:

• You'll be able to go home the day of the procedure.
• You can ask for pain medicine if you need it.
• You'll need someone to drive you home after the procedure.
• It's important to keep the wound clean and dry for up to 5 days after the procedure. This reduces the risk of infection.
• You can return to normal after the procedure. But you may want to rest.
• Tell your doctor if you have bleeding or swelling at the insertion site.

All loop recorders come programmed to record certain fast and slow heart rates. But they also come with a handheld activator that tells the loop recorder to save the signals collected over a certain time. This is important. It can also help explain if a fast or slow heartbeat isn't what's causing your problems. Someone will make sure you know how to use your activator before you go home.

Talk with your heart doctor first if another doctor wants you to get an MRI test. You can get an MRI with a loop recorder. But it may cause your device to display a false reading.

You may keep your loop recorder for up to 3 years. When you no longer need it, you may have it removed in a similar procedure.

Before you agree to the test or procedure make sure you know:

• The name of the test or procedure
• The reason you are having the test or procedure
• What results to expect and what they mean
• The risks and benefits of the test or procedure
• What the possible side effects or complications are
• When and where you are to have the test or procedure
• Who will do the test or procedure and what that person's qualifications are
• What would happen if you did not have the test or procedure
• Any alternative tests or procedures to think about
• When and how you will get the results
• Who to call after the test or procedure if you have questions or problems
• How much you will have to pay for the test or procedure