Objective:

To summarize current evidence on atrial fibrillation (AF) burden and its influence on the clinical benefits of oral anticoagulation (OAC) in the context of evolving monitoring technologies.

Approach:

• Background: AF is a common arrhythmia significantly increasing the risk of ischemic stroke, with OAC reducing this risk by approximately 60%-70%, although it also increases the risk of bleeding.
• Limitations of Traditional Decision-Making: Current anticoagulation decisions are primarily based on the CHA2DS2-VASc score, which assumes a homogeneous stroke risk among AF patients, failing to account for the variability in AF characteristics.
• Challenges from Continuous Monitoring: The rise of continuous rhythm monitoring has led to increased detection of asymptomatic AF, complicating the interpretation of low-burden AF detected outside clinical settings.
• Concept of AF Burden: AF burden is defined as the proportion of monitored time spent in AF, with studies indicating its association with increased thromboembolic risk.

Key Findings:

• Increasing AF burden correlates with higher absolute risks of ischemic stroke and systemic embolism, as shown in observational studies.
• Patients with low AF burden generally exhibit relatively low event rates.
• Randomized trials suggest that in low-burden AF populations, the potential benefits of OAC may be offset by increased bleeding risk.

Interpretation:

AF burden alone is not sufficient for guiding anticoagulation decisions; the net clinical benefit of OAC is influenced by the interplay of AF burden, thromboembolic risk, bleeding risk, and individual clinical factors.

Limitations:

• The study does not provide a definitive guide for anticoagulation decisions based solely on AF burden.
• Variability in AF detection methods may affect the assessment of AF burden, complicating clinical decision-making.

Conclusion:

A comprehensive understanding of AF burden and its clinical implications is essential for optimizing anticoagulation strategies.