Accelerated Implantable Cardiac Monitor (ICM) insertion for the detection of Atrial Fibrillation in Cryptogenic Stroke

• To improve the detection rate of atrial fibrillation (AF) in patients presenting with cryptogenic stroke
• To improve the number of patients eligible for Implantable Cardiac Monitor (ICM) insertion (as per NICE guidance DG41)
• To reduce the waiting time and achieve implantation of ICM prior to discharge in stroke patients
• To reduce the number of hospital visits and consultations during the COVID-19 pandemic
• To increase the proportion of ICM’s implanted by an advanced nurse practitioner

There are more than 100,000 stroke admissions per year and stroke is the fourth leading cause of death in the United Kingdom. In 30-40% of ischaemic strokes the cause is undetermined. Recent studies have shown AF to be a significant cause of stroke which may go undiagnosed. The detection of AF is highly dependent on the length of ECG monitoring.

The CRYSTAL-AF study reported a significant advantage of using long term monitoring over conventional follow up with an AF detection rate of 30% vs 3% at 3 years post stroke with the insertion of the Reveal LINQ™ ICM. Before the published NICE guidance DG41, patients at Eastbourne District General hospital presenting with ischaemic stroke were assessed for atrial fibrillation using:

• A 12 lead ECG on admission
• 24 hour inpatient telemetry
• Outpatient echocardiogram
• Outpatient saline contrast echo if patent for amenovale was suspected.
• 7-day outpatient Holter monitor if atrial fibrillation was still suspected.

The stroke service covers a population of 450,000 pts. An initial audit of this pathway revealed an AF detection rate of 3% in these patients. Thus, the cardiology and stroke team were aware of the potential for AF to be missed with this current pathway and also during the COVID-19 pandemic the pathway became unfeasible due to prolonged waiting lists and cancellations. The COVID-19 pandemic also posed challenges in the management and investigation of stroke patients. These included:

• Limited echocardiograms were performed during the pandemic as per British Society of Echocardiography guidelines.
• The current pathway involved multiple visits to the hospital for investigations, including outpatient echocardiography in the majority of patients and at least two hospital visits for the Holter monitor to be fitted and returned.
• During the COVID-19 pandemic outpatient investigations were suspended.

Given the challenges posed by the COVID-19 pandemic and the awareness of the suboptimal pathway, Eastbourne District General Hospital set up an inpatient pathway following a multi-disciplinary consensus involving stroke physicians and cardiologists. A new pathway was designed performing inpatient echocardiography and begin implanting Reveal LINQ™ ICM’s in patients presenting with cryptogenic stroke, before discharge from hospital.

We formed a multi-disciplinary working group including stroke physicians, cardiologists, physiologists and an advanced nurse practitioner to implement the new pathway. We also took into account feedback from patients and the challenges they faced during the COVID-19 pandemic particularly with shielding and access to healthcare.

Following the consultation, the team developed a pathway for all ischaemic stroke patients presenting to the acute stroke unit. The pathway was primarily implemented by the stroke team with initial investigations including CT/MRI brain imaging, 12 lead ECG, carotid ultrasound, echocardiography and 24 hour telemetry being performed. If atrial fibrillation or an alternative cause for stroke was not found then the stroke team referred the patient to an advanced cardiac nurse practitioner.

If the patient met the inclusion criteria for an ICM, a Reveal LINQ™ ICM was implanted by either the advanced cardiac nurse practitioner or cardiologist under local anaesthetic. The aim was to implant the Reveal LINQ™ within the admission episode. A notable feature of the new pathway was that follow up was performed remotely by the cardiac physiology team. If AF was detected, anticoagulation therapy was initiated without delay by the nurse practitioner in conjunction with the cardiology team. The findings were communicated to the stroke team, patient and general practitioner.

From April 2020 to Dec 2020 a total of 65 patients underwent Reveal LINQ™ implantation for AF detection after a diagnosis of cryptogenic stroke.

56 (86%) ICM implants were successfully performed before discharge from hospital.

42 (65%) ICM implants were performed by our advanced cardiac nurse practitioner.

To date, 7 (9%) cases of significant AF have been identified and these patients have been commenced on anticoagulation therapy.

• The implementation of a one-stop inpatient pathway for investigation of cryptogenic stroke results in a reduced time to ICM implant compared to a conventional outpatient pathway.
• The pathway reduced the number of visits required by patients to the hospital thus improving their experience
• Collaborative working between the stroke and cardiology team improves outcomes in patients presenting with cryptogenic stroke.
• A multidisciplinary approach is essential to rapidly develop and implement a new pathway.
• The use of an advanced cardiac nurse practitioner reduces implant costs and enhances the implementation of the pathway across disciplines.
• A single pathway across disciplines is essential to rapidly initiate anticoagulation therapy when AF is detected in stroke patients.