How safe is it to implant insertable cardiac monitors outside hospital operating rooms? 

Jan Steffer

Writing for Cardiac Rhythm News, Jan Steffel (Zurich, Switzerland) reviews current data and practice regarding safety of insertable cardiac monitors (ICMs) implantation in office settings. 

ICMs are finding increasingly varied applications—not only in cardiology for the diagnosis of syncope—but also for interdisciplinary purposes such as revealing the aetiology and improving the management of cryptogenic stroke.

An important development of these technologies was the introduction of the miniaturised ICM Reveal LINQ (Medtronic) in 2014. Whereas earlier ICMs resembled USB memory sticks, Reveal LINQ measures only 7x45x 4mm, a volume of ~1cm3 or one-third the size of a AAA battery. The small size and the ease of the implant procedure (the insertion opening has the size of <1cm) have expanded both the routine as well as the innovative use of ICMs.

Since the Reveal LINQ can be inserted in a rapid and minimally invasive procedure,2 it is changing the use of hospital resources, helping to drive a shift from performing minor surgical procedures away from cath labs and operating rooms to physicians’ offices. This is part of a wider trend towards more efficient use of surgical, human and financial resources in contemporary healthcare.

Welcome as they may be, out-of-office procedures are uncharted waters for many cardiologists; as such, formal guidelines are not yet available. As an aid to centres considering to implant Reveal LINQ outside the cath lab, we recently published a guidance document3 that provides some key points to take into consideration when setting up such procedures.

As with cath lab procedures, patient safety is a key priority. The need to maintain an adequate sterile environment is as important in office settings as in the hospital. Since ICMs have no direct access to the bloodstream, the greatest risk is that of surgical site infections, which are typically limited to the subcutaneous tissue. With the appropriate procedures in place, our experience is that infections are very rare, <1%, which is less than the typical 2‒4% infection rates recorded for older-generation ICMs in the cath lab4–6 and no higher than published registry data from hospital insertions of Reveal LINQ.7 In the rare case of surgical site infections, these tend to be localised and subcutaneous, and severe consequences are uncommon.

Experiences from colleagues beyond our group seem to agree. At the recent 2017 conference of the American College of Cardiology, an on-going single arm, multicentre study, Reveal In-Office 2 (RIO2; NCT02395536), reported interim data on Reveal LINQ in-office insertion procedures from 191 patients.8 Even though 56% of procedures were performed without antibiotic prophylaxis, no infections were reported and there were no procedure-related complications. One patient had insertion site pain, two had an incision site haemorrhage, and one had vasovagal syncope following the procedure. RIO2 is planned to follow 500 patients and more results will be forthcoming.

However, these encouraging results are no reason for complacency. In spite of being considered “minor”, also these types of surgical procedures come with an inherent risk of complications. As emphasised in our publication, the implementation of uniform, patient-focused care processes will have a crucial role in ensuring that the standard and safety of care remains consistently high. Not all Reveal LINQ insertions are suitable as out-of-office procedures. It is important to study patient profiles before the procedure to identify and exclude those who should not be treated in office settings, including frail elderly patients, those at increased risk for bleeding, as well as patients with diabetes and others in whom post-operative infections may be more common. In-office implantation should also be limited to procedures where the device is inserted in one of the two recommended locations, leaving insertions in alternative locations to dedicated cath labs.

In summary, by embarking onto outpatient out-of-cath lab implantation of these devices, an even larger patient benefit as well as optimisation of resources may be possible. Available evidence supports the safety of insertion procedures outside the cath lab. Nevertheless, as physicians our primary responsibility remains the safety and well-being of our patients.


  1. Pürerfellner H et al. HeartRhythm 2015;12:1113–19
  2. Tomson T T, Passman R. Expert Rev Med Devices 2015;12:7–18
  3. Steffel J et al. Europace 2017;doi:10.1093/europace/euw304
  4. Krahn A D et al. Circulation 1999;99:406–410
  5. Seidl K et al. Europace 2000;2:256–262
  6. Babikar A et al. Int J Clin Pract 2008;62:1520–1525
  7. Mittal S et al. Pacing Clin Electrophysiol 2015;38:1464–1469
  8. Sanders P et al. J Am Coll Cardiol 2017;69:354

Jan Steffel is with the Division of Electrophysiology and Pacing, University Heart Center Zurich University Hospital Zurich, Switzerland. He has received consultant and/or speaker fees from Medtronic. Jan Steffel would like to thank Dr Pelle Stolt for editorial support for this summary