Implanted Cardiac Loop Recorder

Thoracic Foreign Body • Xray of the Week

This patient had a chest Xray for shortness of breath. Is the foreign body a new type of USB drive left in his shirt pocket?

Fig. 1 A. CXR. Foreign body overlying the left side of chest. Fig 1 B. Magnification view showing the detail of the foreign body.

Fig. 2 Radiograph of the Medtronic Reveal LINQ implantable cardiac loop recorder. Note the morphology of the device is the same as the device implanted in this patient. Image courtesy of Medtronics.

Fig. 3. Medtronic Reveal XT implantable cardiac loop recorder compared to the Medtronic Reveal LINQ implantable cardiac loop recorder. Note the Linq is about one tenth the size of the XT. Images courtesy of John Mandrola, MD and Medtronics.

Fig 4. Radiograph (A) and picture (B) of 2 types of USB flash drives. Note the two holes in the A plug on the standard USB flash drive. There are no holes in the compact version.

Fig 5. Chest radiograph of patient with Medtronic Reveal XT implantable cardiac loop recorder.

The implantable cardiac loop recorder is used in patients with recurrent unexplained episodes of palpitations or syncope, for long-term monitoring in patients at risk for or with documented atrial fibrillation, and for risk stratification in patients who have had a myocardial infarction. (1,2,3) The device is implanted subcutaneously in the left parasternal region and stores EKG data automatically in response to a significant arrhythmia. (1,2,3) It is useful either when symptoms are infrequent or when long-term data are required.

The internal loop recorder devices are MRI conditional. (1,4,5,6) The electrical data stored in the loop recorder may be erased or corrupted by the strong magnetic field. Therefore, it is essential for the patient's electrophysiologist to download the data prior to any MRI exam. Since all loop recorders contain ferromagnetic components, there may be motion of the device during a scan. Following MRI, artifacts mimicking arrhythmias are frequently seen internal loop recorder data sets (6).

References:

1. Medtronic REVEAL LINQ™ LNQ11 Insertable Cardiac Monitor. MRI procedural information Manual.

2. Vikas Shah MD: xrayoftheweek 43: that's not a USB stick...is it? The XRay Doctor Blog

3. Medtronic Website. http://manuals.medtronic.com/manuals/main/en_US/manual/index?findby=brandmodel&model=LNQ11

4. Wong JA, Gula LJ, Skanes AC, et al. Feasibility of Magnetic Resonance Imaging in Patients with an Implantable Loop Recorder. Pacing Clin Electrophyisol 2008; 31(3): 333-337.

5. Hilbert S, Jahnke C, Loebe S, et al. Cardiovascular magnetic resonance imaging in patients with cardiac implantable electronic devices: a device-dependent imaging strategy for improved image quality. Eur Heart J Cardiovasc Imaging. 2018 Sep 1;19(9):1051-1061. doi: 10.1093/ehjci/jex243.

6. Medtronic Reveal Loop Recorder information at MRIsafety.com

Kevin M. Rice, MD is the president of Global Radiology CME

Dr. Rice serves as the Medical Director of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a Member of Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015 Dr. Rice and Natalie Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" award for the Most Effective Radiology Educator.

Follow Dr. Rice on Twitter @KevinRiceMD

All posts by Kevin M. Rice, MD