Atrial Fibrillation Burden: New Consensus Definition Aims to Improve Care and Research
An international expert group, led by Prof. Dr. Wolfram Doehner (Charité-Universitätsmedizin Berlin), has proposed a standardized uniform definition of atrial fibrillation burden (AF burden). This recommendation is intended to enhance risk assessment, support therapeutic decision-making, and improve comparability in clinical studies.
The Council on Stroke of the European Society of Cardiology (ESC) in cooperation with the European Heart Rhythm Association (EHRA) the have published a clinical consensus statement on AF burden [https://doi.org/10.1093/europace/euaf019]. The objective of this publication is to establish an internationally harmonized, standardized, and clinically applicable definition of this increasingly relevant parameter to enhance diagnostics, therapy, and research.
 
What is AF Burden and Why is it Relevant?
AF burden refers to the proportion of time a patient experiences atrial fibrillation (AF) during a defined observation period. It is expressed as a percentage. This consensus deliberately deviates from the conventional categorical classification (e.g., paroxysmal, persistent), as studies indicate that the quantitative extent of AF significantly influences symptoms, prognosis, and therapeutic decisions.
A crucial factor in ensuring the comparability of AF burden measurements is the duration of monitoring. Reliable assessment requires continuous or near-continuous ECG monitoring for at least 28 days. Shorter or intermittent ECG monitoring tends to overestimate AF burden while underestimating AF prevalence. Implantable monitors are considered the reference standard, though medically validated patch devices may provide sufficient data under certain conditions. However, short-term, symptom-triggered ECG recordings are not suitable for reliable AF burden assessment.
 
Clinical Relevance in Stroke, Heart Failure, and Cognition
A higher AF burden is associated with an increased risk of stroke, particularly in episodes exceeding 24 hours. In heart failure, especially with preserved ejection fraction (HFpEF), AF burden has been linked to disease progression. Furthermore, studies suggest that high AF burden values may contribute to cognitive impairment. There is also evidence indicating a reduced quality of life with increasing AF burden.
The authors emphasize that no universal threshold exists to determine when AF burden becomes clinically relevant. Rather, thresholds must be validated for specific conditions and depend on individual risk profiles and treatment goals. For stroke risk assessment, the combination of AF burden and the CHA₂DS₂-VASc score may serve as a useful basis.
 
Standardized Definition as a Prerequisite for Progress
With this definition, the ESC and EHRA establish a crucial foundation: improving study comparability, validating disease-specific AF burden thresholds, enabling risk-adapted clinical care, and advancing the development of technologies and algorithms for rhythm monitoring. This standardization supports both clinical decision-making and the scientific and technological advancement of AF therapy.
"We need a reliable and comparable foundation to better assess the clinical benefits of rhythm control, anticoagulation, or ablation in the future," says lead author Prof. Dr. Wolfram Doehner.