Due to copyright issues, an electronic copy of the thesis must be ordered from the faculty. For the faculty to have time to process the order, the order must be received by the faculty at the latest 2 days before the public defence. Orders received later than 2 days before the defence will not be processed. After the public defence, please address any inquiries regarding the thesis to the candidate.
Trial Lecture – time and place
See Trial Lecture.
Adjudication committee
- First opponent: Professor David Z. Rose, University of South Florida
- Second opponent: Professor Anja Bye, Norwegian University of Science and Technology
- Third member and chair of the evaluation committee: Professor Peder Langeland Myhre, University of Oslo
Chair of the Defence
Professor Sahrai Saeed, University of Oslo
Principal Supervisor
Senior Consultant Anne Hege Aamodt, Oslo University Hospital
Summary
Up to 40% of ischemic strokes remain without an identified cause—cryptogenic stroke (CS). A substantial proportion may be due to undiagnosed atrial fibrillation (AF). AF usually does not occur in isolation, but reflects an underlying atrial disease—atrial cardiomyopathy. Insertable cardiac monitors (ICMs) are the most effective method for detecting subclinical AF, but their use is limited, highlighting the need for better patient selection.
This thesis bridges stroke medicine and cardiology. The aim was to explore how atrial cardiomyopathy is reflected in circulating and non-circulating biomarkers, and how these markers relate to AF and CS. All work was based on the Nordic Atrial Fibrillation and Stroke (NOR-FIB) study, a prospective multicenter study of AF occurrence in patients with CS followed with ICMs for 12 months.
Circulating biomarkers were assessed using routine tests and a cardiovascular proteomics panel. NT-proBNP was a strong predictor of incident AF. Proteomics analyses identified growth differentiation factor 15 and inflammation-related proteins as highly discriminatory for AF-related stroke, supporting that systemic signatures of atrial cardiomyopathy can be captured in blood.
Non-circulating biomarkers were evaluated through AF characteristics and brain imaging. AF was detected in nearly one third of patients, and most episodes were asymptomatic and recurrent. Older age, higher pre-stroke embolic risk, vascular risk factors, and specific MRI/CT features were associated with AF, and an imaging-based score identified a subgroup with clearly increased AF risk.
Overall, the findings support the concept that AF is a clinical manifestation of atrial cardiomyopathy, rather than an isolated arrhythmia, and that atrial cardiomyopathy represents a link between AF and CS. Integrating blood-based and imaging biomarkers into risk stratification may improve selection of CS patients for ICM implantation and enhance secondary prevention.
Additional information
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