The Substrate in AF
The atrial substrate has been variably defined, and represents an
umbrella term encompassing the spectrum of alterations in the electrical
properties of the atria associated with AF. A panoply of remodeling
phenomena have been described in experimental models and clinical
studies, and while it remains unclear to what extent each is a cause or
consequence of AF, many possess the potential to facilitate reentry and
thus perpetuate AF. Classically these maladaptive remodeling processes
have been categorized as electrical changes evident at the cellular
level, or structural remodeling at the tissue level. Much of the recent
focus has been on the latter and in particular the deposition of
fibrotic tissue within the atrial landscape, perhaps reflecting the
perception of this representing a more advanced and potentially
irreversible stage of the arrhythmogenic process.