Loop Recorder

A loop recorder is a small device that a cardiologist implants in your chest during a minor, outpatient procedure. The device continuously records your heart rate and rhythm during your daily life. It helps diagnose arrhythmias that other tests, like an EKG, couldn’t detect. The device stays in place as long as needed to reach a diagnosis.


What is a loop recorder?

A loop recorder is a small device implanted underneath the skin of your chest that records your heart’s rate and rhythm. It monitors your heart’s electrical activity 24 hours a day for up to three years. This makes it different from other ambulatory devices that record your heart’s activity for shorter periods of time.

A loop recorder automatically records data and sends it to your cardiologist for review. Such nonstop monitoring helps diagnose abnormal heart rhythms (arrhythmias) such as atrial fibrillation. Arrhythmias can be dangerous and lead to complications like stroke and sudden cardiac arrest. That’s why diagnosis and treatment are so important.

Other names for a loop recorder include:

  • Implantable loop recorder (ILR).
  • Insertable cardiac monitor (ICM).

The loop recorder is located in your chest. It’s placed just under your skin.
An electrophysiologist inserts your loop monitor into the upper left side of your chest. The small device rests just beneath your skin.

An electrophysiologist inserts your loop monitor into the upper left side of your chest. The small device rests just beneath your skin.

What does a loop recorder look like?

A loop recorder is small and rectangular. It’s only about 1 to 2 inches (in.) long and looks similar to a USB memory stick. It’s made of metal and contains an electrical circuit and battery.

The device is subcutaneous, meaning it rests just beneath your skin. You might notice a faint outline of the device under your skin, but it shouldn’t cause any pain or discomfort.

Along with the device inside your chest, your provider will give you a hand-held activator that’s synced with the device. You use this activator any time you have symptoms, like heart palpitations. You simply press a button on this activator to prompt the loop recorder to record your heart’s activity at that moment.

What exactly does a loop recorder do?

A loop recorder monitors your heart rate and heart rhythm. It automatically generates recordings of any abnormal electrical activity and saves the data to its memory bank (much like a USB memory stick). It then sends this data to your cardiologist as often as several times per day.

You can also prompt the device to record and send data if you feel any symptoms. You do this through the hand-held activator. Even if the symptom has passed by then, the device can access and record activity from the past several minutes.

So, the device can record abnormal activity when you notice symptoms, as well as when you notice nothing at all. This data allows your cardiologist to identify abnormal heart activity while also seeing if any symptoms accompany it.

When would I need an implantable loop recorder?

You may need a loop recorder if you have heart palpitations or fainting episodes (syncope), but prior testing hasn’t revealed any arrhythmias. A loop recorder helps your cardiologist diagnose and treat arrhythmias to prevent complications. It can also help your care team rule out heart-related causes of fainting or other symptoms.

Cardiologists use loop recorders to:

  • Identify the cause of fainting episodes or unexplained falls.
  • Evaluate unexplained heart palpitations that keep happening.
  • Monitor heart activity in people with atrial fibrillation, often to help manage treatment.
  • Identify heart rate and rhythm problems in adults with congenital heart disease.
  • Identify abnormal heart rhythms after a stroke.
  • Evaluate low heart rate (bradycardia) before implantation of a permanent pacemaker.
  • Monitor your heart’s electrical activity after a heart attack.

Who performs this procedure?

An electrophysiologist implants your loop recorder. An electrophysiologist is a cardiologist who specializes in your heart’s electrical system.


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Test Details

What happens before a loop recorder is implanted?

Your cardiologist will make sure a loop recorder is appropriate for you. They’ll review your medical history and perform a physical exam. They may order tests, including:

If these tests don’t reveal any heart problems but you still have symptoms (like fainting), you may need a loop recorder.

How do I prepare?

Your cardiologist will tell you how you should prepare. In general, keep in mind:

  • Your cardiologist may tell you to adjust your medications before the procedure. Don’t make any changes unless they tell you to do so.
  • You’ll need someone to drive you home after the procedure. This is because you’ll be sedated for the procedure, and it’s not safe to drive for 24 hours afterward.


How is a loop recorder implanted?

This is an outpatient procedure that doesn’t require general anesthesia. You’ll be awake for the procedure, and you can go home the same day.

To implant your loop recorder, an electrophysiologist performs these steps:

  1. Gives you a mild sedative (to help you relax) and a local anesthetic (so you don’t feel pain during the procedure).
  2. Makes a small cut in your skin on the left side of your chest. The cut may be as small as one quarter of an inch.
  3. Creates a small pocket just under your skin where the device will rest.
  4. Inserts the implantable loop recorder into the pocket.
  5. Closes the opening in your skin with stitches or surgical glue.
  6. Moves a magnet over your chest to activate the device.

The minor procedure takes about 10 to 15 minutes.

What happens afterward?

Most people go home right away and can return to their normal routine. Your cardiologist will tell you how to care for yourself at home, including how to keep your surgical wound clean.

The area around your wound may feel sore, and you may notice bruising. This discomfort is normal and will go away in several days.

Before you go home, your cardiologist will show you how to use the equipment that syncs with your device. These include:

  • A hand-held activator with a button to press when you have symptoms.
  • An electronic transmitter that you keep near your bed. It sends data to your cardiologist on a regular basis.


What are the risks?

This is a low-risk procedure. A small number of people may experience:

  • Infection. If an infection develops at the site of your device, you need antibiotics to treat it. Occasionally, your device may need to be moved to another spot in your chest.
  • Allergic reaction. You may be allergic to a material in the device. In this case, you’ll need another type of monitoring device.
  • Poor signal. Sometimes, the device can’t pick up electrical signals from your heart. Your cardiologist will need to move the device to a different location in your chest.

Can a loop recorder damage your heart?

A loop recorder is safe and doesn’t damage your heart. It also doesn’t change your heart’s pace, provide a shock or do anything to affect your heart’s activity. Instead, it simply monitors your heart’s electrical activity and records anything that’s abnormal.

Results and Follow-Up

How do I know the results?

Your loop recorder automatically sends data to your cardiologist. Your cardiologist will tell you when you need to come in for follow-up appointments to discuss the results.

How long does an implantable loop recorder stay in?

You’ll keep your device long enough for your cardiologist to reach a diagnosis. The timeframe is different for everyone. If the results show you need a pacemaker or implantable cardiac defibrillator, your cardiologist will remove the loop recorder when they insert your new device.

Implantable loop recorders have a long battery life — up to three years. So, there’s plenty of time for the device to identify abnormal rhythms that short-term monitors couldn’t capture.

When should I call my doctor?

Call your cardiologist right away if your incision site has:

  • Redness.
  • Swelling.
  • Bleeding.
  • Pus or discharge.

These can be signs of complications that require immediate care.

Additional Common Questions

What are the pros and cons of a loop recorder?

There are many benefits of a loop recorder. These include:

  • Long-term monitoring. A loop recorder monitors and records your heart’s electrical activity over a long period of time (up to three years). Other monitors cover much less ground. For example, a Holter monitor records 24 hours of activity. There are other types of monitors that can record activity for two weeks. While this is valuable, it’s not enough time to capture abnormal rhythms that people experience once a month or a few times per year. Research shows this long-term monitoring is a huge advantage. According to one study, loop recorders identified more cases of atrial fibrillation the longer they were used. The detection rate among participants was about 9% at six months, 12% at 12 months and 30% at 30 months.
  • Automatic recording. A loop recorder automatically records abnormal heart activity. You don’t have to worry about pushing the button to activate it (though you can when you have symptoms). It can detect abnormalities even when you have no symptoms. This is helpful in instances where you may faint and not remember it. Research shows loop recorders often detect cases of atrial fibrillation that have no symptoms. .
  • Convenience. You can go about your normal routine, including bathing and swimming, with a loop recorder. It’s hidden and no one will see it. It also won’t get in the way as some other monitors might. This helps if you have an active job or lifestyle.

The drawbacks of a loop recorder include:

  • Need for surgery. The device must be implanted under your skin. Even though it’s a minor surgery, there are still risks associated with any surgery.
  • False positives. Sometimes, a loop recorder can show you have atrial fibrillation when in fact you don’t. Your cardiologist will perform other testing to confirm a diagnosis.

What is the difference between a loop recorder and a pacemaker?

A loop recorder doesn’t do anything to change your heart’s electrical activity. It simply monitors your heart rate and rhythm, detecting and recording abnormal activity. A pacemaker is different because it intervenes to correct abnormal heart rhythms, typically very slow rhythms. It detects abnormal rhythms and sends electrical signals that tell your heart to beat.

The loop recorder may show you have an arrhythmia that requires long-term treatment with an implantable device. Such devices include a pacemaker or an implantable cardioverter defibrillator.

Can a loop recorder detect a heart attack?

A loop recorder isn’t intended to detect a heart attack. However, it can detect arrhythmias that develop as a complication of a heart attack.

A heart attack is a medical emergency. If you feel chest pain or other symptoms of a heart attack, don’t wait to seek help. Call 911 or your local emergency number immediately.

Can you drink alcohol with a loop recorder?

Follow your cardiologist’s advice on drinking alcohol and other lifestyle factors. Some research shows that alcohol consumption can cause irregular heart rhythms. This is true when you drink in excess or in moderation (one to two drinks per day).

Research continues to explore this topic. Meanwhile, it’s important to talk to your cardiologist about how alcohol may affect your risk of heart rhythm problems.

A note from Cleveland Clinic

An implantable loop recorder can be a valuable tool for you and your cardiologist to learn the daily activity of your heart. Its data can lead to the diagnosis and treatment of arrhythmias before they cause complications. If you’re anxious about having minor surgery to implant the device, talk to your cardiologist. They can answer your questions and put your mind at ease about this low-risk form of testing.

Medically Reviewed

Last reviewed on 12/18/2022.

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