Author + information
- Received July 8, 2019
- Revision received September 2, 2019
- Accepted September 13, 2019
- Published online November 25, 2019.
- Søren Zöga Diederichsen, MDa,∗ (, )@SDiederichsen,
- Ketil Jørgen Haugan, MD, PhDb,
- Axel Brandes, MD, DMScc,d,
- Mathias Buus Lanng, MSEe,
- Claus Graff, PhDe,
- Derk Krieger, MD, PhDf,g,
- Christian Kronborg, PhDh,
- Anders Gaarsdal Holst, MD, PhDi,
- Lars Køber, MD, DMSca,j,
- Søren Højberg, MD, PhDk and
- Jesper Hastrup Svendsen, MD, DMSca,i,j
- aDepartment of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
- bDepartment of Cardiology, Zealand University Hospital, Roskilde, Denmark
- cDepartment of Cardiology, Odense University Hospital, Odense, Denmark
- dDepartment of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
- eDepartment of Health Science and Technology, Aalborg University, Aalborg, Denmark
- fUniversity Hospital Zurich, University of Zurich, Zurich, Switzerland
- gStroke Unit, Mediclinic City Hospital, Dubai, United Arab Emirates
- hDepartment of Business and Economics, University of Southern Denmark, Odense, Denmark
- iLaboratory for Molecular Cardiology, Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
- jDepartment of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- kDepartment of Cardiology, Bispebjerg Hospital, Copenhagen University Hospital, Copenhagen, Denmark
- ↵∗Address for correspondence:
Dr. Søren Zöga Diederichsen, Department of Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, 2100 København, Denmark.
Background As new heart rhythm monitoring technologies emerge, subclinical atrial fibrillation (AF) signifies a future challenge to health care systems. The pathological characteristics of this condition are largely unknown.
Objectives This study sought to characterize the natural history of subclinical AF in at-risk patients from the general population.
Methods The authors studied 590 individuals ≥70 years of age with ≥1 of hypertension, diabetes, previous stroke, or heart failure, without history of AF, undergoing long-term implantable loop recorder monitoring as part of the LOOP (Atrial Fibrillation Detected by Continuous ECG Monitoring Using Implantable Loop Recorder to Prevent Stroke in High-risk Individuals) study. Baseline assessments included N-terminal pro–B-type natriuretic peptide (NT-proBNP). All day-to-day heart rhythm and symptom data were extracted from the device. Endpoints included AF burden, AF progression, symptom reports, and heart rate during AF.
Results A total of 685,445 monitoring days were available for analysis. Adjudicated AF episodes lasting ≥6 min were detected in 205 participants (35%). The AF burden was median 0.13% (interquartile range: 0.03% to 1.05%) of the monitoring time and changed by a factor of 1.31 (95% CI: 1.02 to 1.68) per doubling of NT-proBNP. AF episodes were present 2.7% (interquartile range: 1.0% to 15.7%) of monitoring days after debut. Progression to 24-h episodes was seen in 33 of the AF patients (16%), whereas 46 (22%) had no AF episodes in the last 6 months of monitoring or longer. Symptoms were absent in 185 (90%) at debut, and 178 (87%) never reported AF-related symptoms during follow-up. The averaged heart rate during AF was 96 (interquartile range: 83 to 114) beats/min, 24 (interquartile range: 9 to 41) beats/min faster than daytime sinus rates.
Conclusions Although previously unknown AF was highly prevalent, the burden was low, and progression was limited. In addition, symptoms were scarce, and the heart rate was only modestly elevated. (Atrial Fibrillation Detected by Continuous ECG Monitoring Using Implantable Loop Recorder to Prevent Stroke in High-risk Individuals [LOOP]; NCT02036450)
This investigator-initiated study was supported by The Innovation Fund Denmark grant 12-135225, The Research Foundation for the Capital Region of Denmark, The Danish Heart Foundation grant 11-04-R83-A3363-22625, Aalborg University Talent Management Programme, Arvid Nilssons Fond, Skibsreder Per Henriksen, R. og Hustrus Fond, and Medtronic. The opinions, results, and conclusions reported in this paper are those of the authors and are independent from the funding sources. Dr. Haugan has received travel and educational grants from Medtronic, Boston Scientific, Abbott, and Biotronik not related to this work; and has received speaker fees from Boehringer Ingelheim not related to this work. Dr. Brandes has received a research grant from Gilead; and has received lecture fees from Bayer, Boehringer Ingelheim, Merck Sharp and Dohme, and Bristol-Myers Squibb not related to this work. Dr. Krieger has been a Medtronic Focus Group member. Dr. Holst is an employee of Novo Nordisk, not related to this work. Dr. Køber has received speaker honoraria from Bayer, AstraZeneca, Orion Pharma, Novartis, and Sanofi, not related to this work; and has served on steering committees for trials sponsored by Novartis. Dr. Svendsen has been a member of Medtronic advisory boards; and has received speaker honoraria and research grants from Medtronic in relation to this work, in addition to a research grant from Gilead, not related to this work. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received July 8, 2019.
- Revision received September 2, 2019.
- Accepted September 13, 2019.
- 2019 American College of Cardiology Foundation
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