Considerations for using atrial fibrillation burden as a surrogate endpoint: A report from the Cardiovascular Sciences Research Consortium

PURPOSE: Atrial fibrillation (AF) care has shifted dramatically, with a focus on early rhythm control to reduce AF-related morbidity and mortality and improve quality of life. However, clinical trials for AF rely on historical definitions of treatment failure, including freedom from recurrence of ≥30 seconds of AF/flutter/tachycardia, which is a poor predictor of AF severity, or traditional clinical endpoints (ie, stroke, heart failure, death) which have low incidence in contemporary AF populations. Therefore, a directly measurable and clinically meaningful measure for these clinical endpoints has the potential to accelerate clinical trials of rhythm control in AF while reducing overall trial overhead. RESULTS: The Cardiovascular Sciences Research Consortium hosted a Think Tank comprising scientists, clinicians, regulators, and industry representatives to develop a roadmap to establish AF burden as a valid surrogate clinical endpoint. This document reviews currently available data to support the use of AF burden as a surrogate endpoint, provides standards for measuring AF burden across measurement modalities and devices, and establishes a practical roadmap for a collaborative approach to validating the use of AF burden. CONCLUSION: Moving beyond historical definitions of AF treatment success and failure, AF burden has the potential to be a patient-centric endpoint that can leverage contemporary monitoring technologies while serving as an early signifier of AF-related risk.