Cardiology



Medtronic’s new Reveal Linq device revolutionises diagnosis





One of the most exciting technological developments in the world of electrophysiology in 2014 has been the launch of Medtronic’s Reveal Linq device. This implantable loop recorder, the size of two matchsticks, replaces the old Reveal XT monitor which was the size of a computer memory stick and which had to be inserted with a small surgical procedure in a cath lab or operating theatre. The new Linq device is simply injected under local anaesthetic in a procedure room and I do not use sedation, intravenous access or even antibiotics.

There is no doubt the tiny size of this new device has lowered the threshold for consideration of implanting a device in patients with infrequent palpitations or loss of consciousness, however, the really revolutionary part of this device is how it communicates the information it detects to doctors and other caregivers. The device comes with a monitor, known as a MyCareLink monitor, which is kept in a patient’s bedroom and simply requires a power socket. Each night at about 2am the device and monitor ‘talk to each other’ using wireless technology. Bradycardias and tachycardias (typically rates <30/min or >180/min) are automatically detected and stored and uploaded via the monitor to the Medtronic remote monitoring portal known as CareLink. This then generates an email to the physician highlighting the arrhythmia.

Case Report

A 67-year-old lady with a history of idiopathic spino-cereballar ataxia and axonal neuropathy presents to a cardiologist in the summer of 2014 having had a sudden collapse whilst at the theatre without prior warning symptoms.

The theatre was hot and it took 20 minutes before she felt back to normal. A systolic murmur is identified on examination but echocardiography gives sub-optimal images and it is difficult to see much more than left ventricular hypertrophy of 1.6cm, good left ventricular systolic function and moderate to severe mitral regurgitation. There was no significant aortic valve gradient but an LV gradient of 255mmHg is detected.

The ECG confirms left ventricular hypertrophy by voltage criteria and sinus rhythm at 63/min. Holter monitoring shows sinus rhythm throughout with only a tiny burden of ventricular ectopy and a further event recorder monitor for 2 weeks detects nothing else. The cardiologist assumes there is hypertensive heart disease but is unsure whether this was a Stokes-Adams attack or a simple faint and after the patient has another episode of syncope, she is referred to me for insertion of a Reveal Linq device.

I implanted a Reveal Linq device on the 15th of October in a procedure room under local anaesthetic alone; the actual procedure itself taking only 2 minutes and the patient went home shortly afterwards having been instructed on the use of the MyCareLink monitor and device activator.

Nineteen days later I awoke to receive an email from the Medtronic CareLink to let me know the patient had had an automatically detected event triggering an alert. I logged into the CareLink system from my home and downloaded the information.

The ‘dot-plot’ graph showed the onset of a very rapid tachycardia at 250/ min lasting 15 seconds, before abruptly slowing and then a further period of a slower irregular tachycardia between 100-200/min. The ECG showed the onset of a slightly irregular but essentially monomorphic broad complex tachycardia, most likely ventricular tachycardia. The subsequent tachycardia (with ECGs not stored on the device) is most likely atrial fibrillation. I contacted the patient and found she had collapsed earlier that morning at the same time as the event above and I therefore arranged urgent admission to hospital.



A cardiac MRI scan was performed the following day (MRI scans are possible with the Reveal Linq device, although one should normally wait 6 weeks after implant and data should be manually downloaded before the scan and the device checked again immediately afterwards). The scan showed typical features of hypertrophic cardiomyopathy with asymmetric left ventricular hypertrophy of 2.4cm, systolic anterior motion of the anterior mitral valve leaflet, crypts in the myocardium at the LV apex, hypertrophied papillary muscles displaced apically and LVOT obstruction and severe mitral regurgitation. There was minimal late enhancement.

She was reviewed by an expert in cardiomyopathies, who confirmed the diagnosis and also confirmed that Friedrich’s ataxia (commonly associated with hypertrophic cardiomyopathy) had previously been excluded with genetic testing. Familial screening was then implemented. Low dose beta-blockade was started and I then implanted a dual chamber, MRI-conditional, single coil Medtronic Evera ICD without complication and the Reveal Linq device was explanted. This ICD, like the Reveal Linq, is revolutionary in that it is licensed for full body MRI scans after a six-week waiting period (and with appropriate device testing before and afterwards). In this case this means the patient can continue to have MRI scans performed of the brain and spinal cord for her neurological conditions. The patient was discharged home the following day and remains under close review. This case demonstrates the breakthrough the Reveal Linq device represents in facilitating diagnosis of intermittent, infrequent or alarming arrhythmias or black-outs and immediately alerting their physician of serious heart rhythm problems. In this particular case, this meant admission to hospital and life-saving treatment was implemented without delay and then rapid discharge home.

The Author

Dr Oliver Segal MBBS, MD, FRCP, FHRS is a Consultant Cardiologist & Electrophysiologist at London Medical (www.londonmedical.co.uk) and The Heart Hospital, University College London Hospitals, UK.  

 Date of upload: 10th Jan 2015

 

                                  
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