How Is a Loop Recorder Inserted? The Procedure Explained

A loop recorder is inserted through a small incision on the chest, typically just to the left of the breastbone, under local anesthesia. The device itself is roughly the size of a small USB flash drive, and the entire procedure often takes less than fifteen minutes. Because the incision is only about a centimeter long and the device sits just beneath the skin rather than inside the heart, the insertion is considered a minor procedure, closer to getting stitches than to open surgery.

What the Device Looks Like and Where It Goes

An implantable loop recorder, sometimes called an insertable cardiac monitor, is a slim rectangular device with two electrodes on its surface. Over the past two decades, these monitors have shrunk dramatically. The newest models are roughly a third the volume of their predecessors, which has simplified the insertion process and made the resulting scar less visible.¹ That miniaturization also means the device can be placed in locations that would have been impractical with the older, bulkier models.

The device sits in the subcutaneous tissue, the layer of fat and connective tissue just beneath the skin and above the muscle. It does not touch the heart or enter a blood vessel. Its two electrodes sense the electrical activity of the heart through the surrounding tissue, much like a surface electrocardiogram but from closer range. The quality of that signal depends on how the device is oriented relative to the heart, which is why placement position matters.

Research using electrical mapping of the chest has shown that the strongest heart signals appear when the device is positioned vertically along the left side of the breastbone, in the space between the third and fifth ribs. Angling the device at roughly 45 degrees in certain positions can also produce acceptable signals.² In practice, the physician tests the signal during the procedure and adjusts the device if needed before closing the incision.

The Insertion Itself, Step by Step

The procedure begins with cleaning the chest and draping the area to keep it sterile. Local anesthetic, usually a mix of lidocaine and bupivacaine with epinephrine, is injected into the skin and the tissue underneath at the planned insertion site. About five milliliters is typical.³ The epinephrine constricts blood vessels at the site, which reduces bleeding and helps the anesthetic last longer. Within a couple of minutes the area goes numb.

The physician then makes a small incision, roughly one centimeter, and uses either the device’s own insertion tool or a blunt-tipped instrument to create a shallow pocket in the subcutaneous tissue. The device slides into this pocket. A quick check of the signal quality follows: the team verifies that the monitor can detect an adequate heartbeat tracing. If the signal is too weak, the device may be repositioned or angled differently. Once the signal looks good, the incision is closed with adhesive strips, a stitch or two, or surgical glue. A small dressing covers the site.

Modern devices have made the procedure simple enough that it can be performed without a full surgical suite. They can be placed at a patient’s bedside, in a procedure room, or in a physician’s office, not just in a hospital operating room or catheterization lab.⁴

Office Versus Hospital Setting

One of the bigger practical shifts in recent years is the move toward in-office insertion. A randomized trial of 482 patients compared office insertion with hospital-based insertion and found that the procedure succeeded in every single patient in both groups. The complication rates were nearly identical: under 1% in the office and under 1% in the hospital. Adverse events of any kind, including minor ones, occurred in about 2.5% of office cases and about 4.4% of hospital cases.⁵

The office setting also turned out to be more efficient. Total visit time from check-in to discharge was about 107 minutes shorter in the office compared with the hospital. Staff time per case was roughly 75% higher in the hospital, which translated to about 50% higher staffing costs.⁶ Physicians in the trial also reported fewer scheduling delays in the office and rated the convenience much higher. Patients generally responded more positively to the office experience as well.⁵

Not every patient is a candidate for an office insertion. People who need sedation beyond what a typical office can provide, or who have medical conditions that warrant closer monitoring during the procedure, will still be directed to a hospital or electrophysiology lab. But for the majority of patients, an office insertion is safe, faster, and cheaper.

What to Expect With Pain and Recovery

During the procedure itself, most people feel pressure or a brief sting when the local anesthetic is injected, but the insertion is painless once the area is numb. Some centers offer mild sedation on top of the local anesthetic, though this is optional and often unnecessary.³ The entire insertion typically takes under fifteen minutes from the first injection to placing the bandage, which is one reason sedation is often skipped.

Afterward, the incision site may be sore for a few days, similar to a minor cut. Over-the-counter pain relievers usually handle it. You’ll be told to keep the area dry for a short period and to watch for signs of infection, like increasing redness, warmth, or discharge. Most people return to normal activities the same day or the day after. Heavy lifting or vigorous upper-body exercise is usually restricted for a week or so to let the pocket heal and prevent the device from shifting.

Complications and What Can Go Wrong

Serious complications from loop recorder insertion are uncommon, but they do happen. An analysis of adverse events reported to the FDA’s device reporting database found that the most frequently reported patient problems were pain or discomfort, accounting for about 27% of reported events. Site infection made up about 21%, device erosion through the skin about 13%, and impaired wound healing about 5%.⁷

A few things to keep in mind about those numbers. The FDA database captures voluntarily reported events, which means it skews toward problems: routine, uneventful insertions don’t generate reports. The absolute rate of complications in controlled trials is far lower. In the randomized trial comparing office and hospital settings, the combined rate of insertion failures and device-related complications was under 1% in both groups.

Infection, when it occurs, usually responds to antibiotics, but occasionally the device needs to be removed. Erosion, where the device works its way toward or through the skin surface, tends to happen in very thin patients who don’t have much subcutaneous tissue to cushion the device. Device migration, where the recorder shifts from its original position, has also been documented, though it is rare with modern devices and careful pocket creation.¹

Children and Other Special Cases

Loop recorders are used in children as well, but the insertion requires more thought about where to put the device. Kids, especially younger ones, often have very thin subcutaneous tissue on the chest. Placing the device in the standard left parasternal position can leave a visible bulge or increase the risk of erosion. A study of pediatric patients found that when the chest tissue was too thin, physicians opted for an infraclavicular position instead, tucking the device below the collarbone with its antenna directed toward the heart. This alternative site also proved cosmetically preferable for families concerned about scarring.⁸

The choice between the two positions was guided by each child’s weight, chest dimensions, and tissue thickness. All pediatric procedures in that study were performed in a cardiac catheterization lab rather than an office, reflecting the added caution that comes with working on smaller patients. General anesthesia or deeper sedation is more commonly used in children who cannot hold still for the procedure.

Why a Loop Recorder Instead of an External Monitor

If you’ve been offered a loop recorder, you’ve probably already worn a Holter monitor or some kind of external cardiac monitor. The reason doctors escalate to an implanted device is diagnostic yield: the odds of actually catching what’s going on with your heart rhythm are substantially higher with a device that monitors continuously for months or years rather than days.

A randomized trial comparing external loop recorders to standard Holter monitors found that the loop recorder identified or excluded an arrhythmia in 56% of patients with fainting or near-fainting episodes, compared with 22% for the Holter.⁹ Traditional Holter monitors, worn for 24 to 48 hours, have a diagnostic yield of roughly 15 to 28%, while external loop recorders push that to around 63%.¹⁰ An implantable loop recorder pushes even further, because it can sit in place for up to three years, waiting for an event that might happen only once every few months.

This advantage is especially pronounced in detecting atrial fibrillation after a stroke. A meta-analysis pooling seven studies found that patients who received an implantable loop recorder were more than three times as likely to have atrial fibrillation detected compared with those monitored by conventional means.¹¹ Finding atrial fibrillation matters because it changes treatment: patients can be started on blood thinners that reduce the risk of another stroke.

How the Device Sends Data After Insertion

Once the loop recorder is in place, it continuously records a short loop of your heart’s electrical activity, overwriting the oldest data as new data comes in. When the device detects something abnormal, or when you press a handheld activator because you feel symptoms, it saves that segment permanently. Saved recordings are transmitted wirelessly to a secure server, where your doctor’s team reviews them. This remote monitoring setup means you don’t need to go into the office every time the device picks something up.

Most current devices use a bedside transmitter or pair with a smartphone app. You keep the transmitter on your nightstand or within range, and the device uploads data automatically, usually overnight. Your clinical team receives alerts for significant events and can review stored tracings without scheduling an in-person visit. Periodic in-office follow-ups are still recommended, but much of the surveillance happens remotely.

False Alarms and AI Filtering

One longstanding frustration with loop recorders has been false-positive alerts. The device flags something that looks like an arrhythmia on its limited single-channel recording but turns out to be noise, muscle artifact, or a harmless rhythm variant. Clinicians then have to sift through these alerts, which consumes time and can cause unnecessary anxiety for patients.

Newer devices address this with built-in artificial intelligence filters. A study of an AI-based deep neural network filter found that it improved the accuracy of atrial fibrillation detection from about 54% to roughly 75%, with the biggest gains for short episodes that are hardest for conventional algorithms to classify. The most common cause of false alarms was premature atrial contractions, which the AI learned to distinguish from true atrial fibrillation. The filter achieved this improvement without missing meaningful episodes of arrhythmia.¹²

Devices with these AI algorithms and remote reprogramming capability have been shown to reduce the overall alert burden for clinicians, maintaining high detection rates for real arrhythmias while cutting down on the noise.¹³ This is an area that continues to evolve rapidly, and the next generation of devices will likely be even better at sorting clinically meaningful events from artifacts.

How Having a Loop Recorder Affects Anxiety

Living with unexplained heart symptoms, especially fainting episodes or palpitations with no clear cause, is stressful. Some patients worry that having a device implanted will make them more anxious, essentially turning them into someone who is perpetually “being monitored.” The evidence suggests the opposite. A study tracking anxiety scores before and after loop recorder placement found that patients’ average anxiety levels dropped by half at six weeks and by 73% at twelve weeks after the device was implanted. Women showed especially strong improvement, with anxiety scores dropping by 81% at twelve weeks compared with 66% for men.¹⁴

The likely explanation is reassurance. Once the device is in place, patients know that if something dangerous happens with their heart rhythm, it will be caught. That sense of being covered seems to outweigh the abstract discomfort of having an implanted monitor. For people whose symptoms have been elusive and frightening, finally having a reliable way to capture what’s happening appears to be genuinely calming.

Cost Considerations

Loop recorders are not cheap. The device itself, the insertion procedure, and the ongoing remote monitoring fees add up. A study of post-stroke patients in the U.S. found that the total cost of care around the time of device placement averaged about $34,000, compared with roughly $21,000 for patients who received long-term external monitors and about $17,000 for those given Holter monitors. Out-of-pocket costs for the device group averaged around $854, versus $64 for external continuous monitors and $27 for Holter monitors.¹⁵

Whether that extra cost is worthwhile depends on the clinical situation. For patients with unexplained fainting suspected to be caused by a heart rhythm problem, economic modeling has found loop recorders to be cost-effective compared with doing no further testing, at roughly £16,400 to £17,400 per quality-adjusted life year gained.¹⁶ That falls well within the range that health systems generally consider worthwhile.

The picture is less clear when the device is used for broad screening. A Danish trial of loop recorders placed in people aged 70 to 90 to screen for atrial fibrillation found that within a three-year window, the screening was not cost-effective at any reasonable willingness-to-pay threshold. The quality-of-life gain was too small over that time frame to justify the cost.¹⁷ The takeaway is that loop recorders earn their keep when implanted in patients who already have symptoms or a strong clinical reason for long-term monitoring, rather than as a general screening tool in older adults.

When the Device Comes Out

Removal is even simpler than insertion. The physician numbs the area over the device, makes a small incision along or near the original scar, and pulls the device out. There’s no deep tissue involvement and no leads to extract. The whole removal takes a few minutes. Some patients keep the device in place indefinitely after its battery dies if removal isn’t medically necessary, since the inactive device poses no known risk just sitting in the subcutaneous tissue. Others have it replaced with a new unit if ongoing monitoring is still needed, using the same pocket or a nearby one.

If a second device replaces the first, the physician will typically evaluate the original pocket site carefully. Reusing the same pocket is convenient but requires making sure the tissue is healthy and that the first device hasn’t caused thinning of the overlying skin. When the tissue looks good, the swap is straightforward. When it doesn’t, a new pocket is created a short distance away.

1
PubMed Central. The Case of the Migrating Loop Recorder
2
PubMed Central. Investigation of optimal position for implantable loop recorders by potential mapping with Reveal DX
3
Biomedical Journal of Scientific & Technical Research. ILRs- Implantable Loop Recorders, Insertion Guidance and After Care Precautions- A Review and Reflection of the Literature and Our Experience
4
PubMed Central. Subcutaneouscardiac Rhythm Monitors: A Comprehensive Review.
5
PubMed. In-office insertion of a miniaturized insertable cardiac monitor: Results from the Reveal LINQ In-Office 2 randomized study
6
PubMed. Resource utilization associated with hospital and office-based insertion of a miniaturized insertable cardiac monitor: results from the RIO 2 randomized US study
7
PubMed. Adverse events of subcutaneous loop recorders: Insights from the MAUDE database
8
PubMed Central. Implantable Loop Recorder with Long Sensing Vector: Safety, Acceptability, and Sensing Performance in Pediatric Patients
9
The American Journal of Medicine. A prospective randomized comparison of loop recorders versus Holter monitors in patients with syncope or presyncope
10
Arrhythmia & Electrophysiology Review. Holter Monitoring and Loop Recorders: From Research to Clinical Practice
11
PubMed Central. Value of implantable loop recorders in detecting atrial fibrillation for stroke prevention: a systematic review and meta-analysis
12
PubMed. AI Filter Improves Positive Predictive Value of Atrial Fibrillation Detection by an Implantable Loop Recorder
13
PubMed Central. Monitoring of Remotely Reprogrammable Implantable Loop Recorders With Algorithms to Reduce False-Positive Alerts
14
Oxford Academic (European Heart Journal). Assessing the impact of implantable loop recorder placement on anxiety level
15
PubMed Central. Effectiveness, utilisation and cost associated with implantable loop recorders versus external monitors after ischaemic or cryptogenic stroke
16
EP Europace. Implantable loop recorders are cost-effective when used to investigate transient loss of consciousness which is either suspected to be arrhythmic or remains unexplained
17
PubMed. The cost-effectiveness of implantable loop recorder detection of atrial fibrillation to prevent stroke in persons at high risk: An economic evaluation alongside a multicentre randomised controlled trial in Denmark (The LOOP Study)