Atrial fibrillation in cryptogenic stroke and transient ischaemic attack - The Nordic Atrial Fibrillation and Stroke (NOR-FIB) Study: Rationale and design

Barbara Ratajczak-Tretel; Anna Tancin Lambert; Henriette Johansen; Bente Halvorsen; Vigdis Bjerkeli; David Russell; Else Charlotte Sandset; Hege Ihle-Hansen; Erik Eriksen; Halvor Næss; Vojtech Novotny; Andrej Netland Khanevski; Thomas C Truelsen; Titto Idicula; Karen L Ægidius; Håkon Tobro; Siv B Krogseth; Håkon Ihle-Hansen; Guri Hagberg; Christina Kruuse; Kathrine Arntzen; Grete K Bakkejord; Maja Villseth; Ingvild Nakstad; Guttorm Eldøen; Raheel Shafiq; Anne Gulsvik; Martin Kurz; Mehdi Rezai; Jesper Sømark; Stein-Helge Tingvoll; Christine Jonassen; Susanne Ingebrigtsen; Linn Hofsøy Steffensen; Christine Kremer; Dan Atar; Anne Hege Aamodt

doi:10.1177/2396987319837089

Atrial fibrillation in cryptogenic stroke and transient ischaemic attack - The Nordic Atrial Fibrillation and Stroke (NOR-FIB) Study: Rationale and design

Eur Stroke J. 2019 Jun;4(2):172-180. doi: 10.1177/2396987319837089. Epub 2019 Mar 19.

Authors

Barbara Ratajczak-Tretel^{1

2}, Anna Tancin Lambert^{1

2}, Henriette Johansen³, Bente Halvorsen^{4

2}, Vigdis Bjerkeli⁴, David Russell^{3

2}, Else Charlotte Sandset³, Hege Ihle-Hansen⁵, Erik Eriksen³, Halvor Næss⁶, Vojtech Novotny⁶, Andrej Netland Khanevski⁶, Thomas C Truelsen⁷, Titto Idicula⁸, Karen L Ægidius⁹, Håkon Tobro¹⁰, Siv B Krogseth¹¹, Håkon Ihle-Hansen¹², Guri Hagberg¹², Christina Kruuse¹³, Kathrine Arntzen¹⁴, Grete K Bakkejord¹⁴, Maja Villseth¹⁵, Ingvild Nakstad¹⁵, Guttorm Eldøen¹⁶, Raheel Shafiq¹⁶, Anne Gulsvik¹⁷, Martin Kurz¹⁸, Mehdi Rezai¹⁸, Jesper Sømark¹⁹, Stein-Helge Tingvoll¹⁹, Christine Jonassen^{20

21}, Susanne Ingebrigtsen²², Linn Hofsøy Steffensen²², Christine Kremer^{23

24}, Dan Atar^{2

25}, Anne Hege Aamodt³

Affiliations

¹ Department of Neurology, Østfold Hospital Trust, Grålum, Norway.
² Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
³ Department of Neurology, Oslo University Hospital, Oslo, Norway.
⁴ Research Institute of Internal Medicine, Oslo University Hospital, Oslo, Norway.
⁵ Department of Geriatric Medicine, Oslo University Hospital, Oslo, Norway.
⁶ Department of Neurology, Haukeland University Hospital, Bergen, Norway.
⁷ Department of Neurology, Rigshospitalet University Hospital, Copenhagen, Denmark.
⁸ Department of Neurology, St. Olav University Hospital, Trondheim, Norway.
⁹ Department of Neurology, Bispebjerg University Hospital, Copenhagen, Denmark.
¹⁰ Department of Neurology, Telemark Hospital, Skien, Norway.
¹¹ Department of Neurology, Vestfold Hospital, Tønsberg, Norway.
¹² Department of Internal Medicine, Vestre Viken Hospital Trust, Bærum Hospital, Bærum, Norway.
¹³ Department of Neurology, Herlev Gentofte Hospital, Copenhagen, Denmark.
¹⁴ Department of Neurology, Nordlandssykehuset, Bodø, Norway.
¹⁵ Department of Neurology, Drammen Hospital, Vestre Viken Hospital Trust, Drammen, Norway.
¹⁶ Department of Neurology, Molde Hospital, Molde, Norway.
¹⁷ Department of Internal Medicine, Diakonhjemmet Hospital, Oslo, Norway.
¹⁸ Department of Neurology, Stavanger University Hospital, Stavanger, Norway.
¹⁹ Department of Neurology, Innlandet Hospital Trust, Lillehammer, Norway.
²⁰ Center of Laboratory Medicine, Østfold Hospital Trust, Grålum, Norway.
²¹ Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
²² Department of Neurology, University Hospital of North Norway, Tromsø, Norway.
²³ Department of Neurology, Skåne University Hospital, Malmö, Sweden.
²⁴ Department of Clinical Sciences, Lund University, Malmö, Sweden.
²⁵ Department of Cardiology B, Oslo University Hospital, Ullevål, Oslo, Norway.

Abstract

Purpose: Paroxysmal atrial fibrillation is often suspected as a probable cause of cryptogenic stroke. Continuous long-term ECG monitoring using insertable cardiac monitors is a clinically effective technique to screen for atrial fibrillation and superior to conventional follow-up in cryptogenic stroke. However, more studies are needed to identify factors which can help selecting patients with the highest possibility of detecting atrial fibrillation with prolonged rhythm monitoring. The clinical relevance of short-term atrial fibrillation, the need for medical intervention and the evaluation as to whether intervention results in improved clinical outcomes should be assessed.

Method: The Nordic Atrial Fibrillation and Stroke Study is an international, multicentre, prospective, observational trial evaluating the occurrence of occult atrial fibrillation in cryptogenic stroke and transient ischaemic attack. Patients with cryptogenic stroke or transient ischaemic attack from the Nordic countries are included and will have the Reveal LINQ® Insertable cardiac monitor system implanted for 12 months for atrial fibrillation detection. Biomarkers which can be used as predictors for atrial fibrillation and may identify patients, who could derive the most clinical benefit from the detection of atrial fibrillation by prolonged monitoring, are being studied.

Conclusion: The primary endpoint is atrial fibrillation burden within 12 months of continuous rhythm monitoring. Secondary endpoints are atrial fibrillation burden within six months, levels of biomarkers predicting atrial fibrillation, CHA₂DS₂-VASc score, incidence of recurrent stroke or transient ischaemic attack, use of anticoagulation and antiarrhythmic drugs, and quality of life measurements. The clinical follow-up period is 12 months. The study started in 2017 and the completion is expected at the end of 2020.

Keywords: Cryptogenic stroke; Nordic Atrial Fibrillation and Stroke Study; anticoagulation; arrhythmia monitoring; atrial fibrillation; biomarkers; insertable cardiac monitor.