The Concept of "Burden" in Atrial Fibrillation.

Over the last decade or so the term "burden" has become frequently encountered in manuscripts discussing atrial fibrillation (AF). AF "burden" is perhaps most commonly encountered in the electrophysiological context - the amount of time the patient is in AF out of the total monitored time (i.e., the percent of time one is in AF). However, "burden" in AF may also be used in other contexts, which we characterize below as "disease burden", "clinical burden," "economic burden." Over the course of the disease progression and its therapy, such "burdens" may change, and may do so in parallel with each other or in opposite directions. This manuscript explores these various concepts of AF "burden" so as to emphasize to authors and readers that when using the term, its meaning must be made clear.