The purpose of this observational study is to investigate whether blood tests related to blood clotting are associated with established clinical stroke risk scores, the total amount of device-detected atrial fibrillation recorded by an implanted cardiac device, and ultrasound measurements of the heart in people with device-detected atrial fibrillation. The study will also evaluate whether these baseline measurements are associated with future clinical outcomes and may improve future stroke risk assessment.
Device-detected atrial fibrillation is an irregular heart rhythm detected by implanted cardiac devices such as pacemakers, implantable cardiac monitors, and implantable defibrillators. It is often brief and does not cause symptoms. Although it increases the risk of stroke and systemic embolism, the risk is lower than in people with clinically diagnosed atrial fibrillation. As a result, it remains difficult to identify which patients are most likely to benefit from blood-thinning medication, which reduces the risk of stroke but also increases the risk of bleeding.
The study will include 222 participants with implanted cardiac devices, including 111 participants with device-detected atrial fibrillation and 111 age-, sex-, and cardiac device indication-matched control participants without device-detected atrial fibrillation. At baseline, participants will undergo blood sampling, ultrasound examination of the heart, and routine device interrogation. Information on medical history and established clinical stroke risk factors will also be collected. The implanted cardiac device will be used to determine the total amount of device-detected atrial fibrillation recorded during the year before study inclusion.
The baseline analyses will investigate whether established clinical stroke risk scores, the total amount of device-detected atrial fibrillation, and heart ultrasound findings are associated with changes in blood clotting that may indicate an increased tendency to form blood clots. The study will evaluate both primary and additional blood clotting markers to improve the understanding of the biological mechanisms underlying thromboembolic risk in device-detected atrial fibrillation.
Participants will subsequently be followed for 10 years to determine whether baseline blood clotting markers, the total amount of device-detected atrial fibrillation, heart ultrasound findings, and clinical stroke risk scores are associated with future clinical outcomes, including stroke, systemic embolism, hospitalization, death, progression to clinically diagnosed atrial fibrillation, and initiation of oral anticoagulant therapy.
The findings may improve the understanding of thromboembolic risk in people with device-detected atrial fibrillation and support the development of more individualized approaches to future stroke risk assessment and treatment.
Age > 50 years at inclusion
Implanted cardiac device with an atrial electrode
≥1 episode of device-detected atrial fibrillation lasting ≥1 minute, detected at routine cardiac device interrogation within the last 12 months
Written informed consent obtained prior to inclusion
History of ECG-documented atrial fibrillation at any time prior to inclusion
Use of oral anticoagulation or dual antiplatelet therapy within 6 months prior to inclusion, irrespective of indication
Current treatment with oral contraceptives or hormone replacement therapy
Pregnancy or breastfeeding
Participants will be recruited from the Department of Cardiology, Esbjerg and Grindsted Hospital, University Hospital of Southern Denmark. The study population comprises adults with implanted cardiac devices undergoing routine outpatient device interrogation. The device-detected atrial fibrillation cohort will include participants with at least one episode of device-detected atrial fibrillation lasting ≥1 minute identified during routine device interrogation within the previous 12 months. The control cohort will comprise participants without device-detected atrial fibrillation during the previous 4 years, recruited from the same outpatient population and matched on age, sex, and indication for cardiac device implantation. All participants will be enrolled consecutively from a single-center cardiology outpatient clinic.
Cohort
Prospective
Not listed
Thrombin generation assessed by endogenous thrombin potential
Thrombin generation plays a pivotal role in blood clotting and thus serve as primary outcome measure. Thrombin generation will be assessed through measurement of endogenous thrombin potential (nmol/L x min), using the calibrated automated thrombography (CAT) method.
Levels of von Willebrand factor (vWF) antigen
von Willebrand factor plays an important role in platelet plug formation. von Willebrand factor antigen (%) will be measured using an in-house immunoassay.
Plasma P-selectin Concentration
Plasma concentration of soluble P-selectin antigen (ng/ml) measured using an enzyme-linked immunosorbent assay (ELISA). P-selectin will only be measured in participants with elevated von Willebrand factor antigen concentrations.
Thrombin generation assessed by lag time
Thrombin generation plays a pivotal role in blood clotting. Thrombin generation will be assessed through measurement of lag time (min), using the calibrated automated thrombography (CAT) method.
Thrombin generation assessed by peak thrombin concentration
Thrombin generation plays a pivotal role in blood clotting. Thrombin generation will be assessed through measurement of peak thrombin concentration (nmol/L), using the calibrated automated thrombography (CAT) method.
Thrombin generation assessed by time to peak
Thrombin generation plays a pivotal role in blood clotting. Thrombin generation will be assessed through measurement of time to peak (min), using the calibrated automated thrombography (CAT) method.
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Andreas Sjøholm-Christensen
Lead sponsor
University of Southern Denmark
Sponsor institution
Sydvestjysk Kardiologisk Fond
Collaborator
Grosserer L.F. Foghts Foundation
Collaborator
Region of Southern Denmark
Collaborator
Karola Jørgensens Foundation and Foundation for Cardiology in Southwest Denmark.
Collaborator
The A.P. Moeller Foundation
Collaborator
OPEN, Open Patient data Explorative Network, Odense University Hospital, Region of Southern Denmark
Collaborator
The Simon Spies Foundation
Collaborator
The foundation of Fam. Kjærsgaard, Sunds
Collaborator
