Publish date: 22 April 2022

Stroke patients at the National Hospital for Neurology and Neurosurgery (NHNN) are being implanted with heart monitors when the cause or origin of their stroke is unclear (known as cryptogenic stroke), making the stroke team the first in the NHS to carry out the implants on patients rather than refer them to a cardiology service.

The cardiac monitors detect atrial fibrillation (AF) in cryptogenic strokes or transient ischaemic attacks (TIA). One in four strokes and half of all TIAs do not present a cause after standard work up.

Missed AF is often suspected as the cause of cryptogenic stroke but long-term monitoring of a patient’s heart rhythm, which can take up to three years, is required to confirm this. AF can be intermittent, short lived and asymptomatic making it challenging to identify. Long-term monitoring reveals AF in around one in six cryptogenic stroke patients. 

AF can only be treated if it is detected. The sooner the cause is identified, the sooner the patient can be put on the right treatment. Early identification and rapid initiation of anticoagulation has been shown to reduce risk of further strokes by two-thirds and could prevent around 7,000 strokes a year. Strokes attributed to AF are often more severe, with higher mortality and greater disability.

UCLH stroke nurse practitioners, Selina Edwards and Roberto Macarimban-Inglesant are the first stroke nurses trained to implant these miniature devices under the skin within a stroke-led service. The devices are tiny, one-third of the size of an AAA battery.

The nurses manage the monthly Loop Recording Clinic at the NHNN and have successfully implanted eight patients to date with positive feedback. Keeping the implantation within the stroke service speeds up the process of getting patients set up with monitoring and then getting them started on stroke-preventing anticoagulant treatment, if appropriate.

Selina said: “It can be very unsettling for our patients not knowing what caused their stroke and then living with the anxiety that it could happen again. As a nurse, it is gratifying to be able to carry out the procedure in a timely way so our patients can feel reassured that that their heart rhythm is being constantly monitored to pick up any potential signs of what the problem may be. As soon as we know, we can then get them on the appropriate treatment to prevent further strokes.”

The use of the Reveal LINQ II™ device made by Medtronic was approved by NICE in September 2020 as an option to help to detect AF after cryptogenic stroke and TIAs. The guidance says it should be used after non-invasive ECG monitoring has been carried out and no other cause for the stroke has been found. The NHNN is running a pilot of 20 cases in a bid to gather evidence to make a formal business case to commissioners.

Implanting a cardiac monitor is a simple, quick procedure, carried out in an outpatient setting. The patient is given a small electronic transmitter to keep at home. The patient’s heart rhythms are sent via a mobile app or a small electronic monitor using Bluetooth technology, and the results are monitored remotely by stroke nurses and cardiac physiologists. ICMs can continuously monitor cardiac rhythm for three to five years after implantation.

NHNN consultant neurologist Dr Arvind Chandratheva said: “There are a significant number of strokes where the cause is not clear. Being able to monitor our patients with the implantable loop recorders as quickly as possible to establish if atrial fibrillation is the cause is a huge step forward. Not only does it help to reassure patients, it means that we in the stroke service can manage their care throughout. This service highlights timely investigation and continuity of care,” said Arvind, who is also the operational lead for stroke in North Central London.

“The project has involved close collaboration with cardiology, the nursing team and the senior management team and is a response to patient feedback. Selina and Roberto have been key to making this happen.”

Jasper Dade, 55, had an implant fitted by Selina on 31 January. He was referred to the Loop Recording Clinic by his neurologist, after suffering from balance, speech and memory issues following three strokes between 2017 and 2019.

Jasper says that at the time he did not realise what was happening so didn’t seek medical attention. “Getting the implant was very straightforward. It went really well and was a good experience. I recovered very quickly with very little bruising and swelling. Selina was amazed that she couldn’t even see the entry point when she reviewed me in clinic one week later.

“I have episodes, they feel like heart palpitations, usually when I am in bed. It is good to know that all of this is now being recorded so that Selina and colleagues can monitor it over time and work out what the problem is.”