The Role of Mechano-Electrical Feedback in the Cholinergic Atrial Fibrillation Initiation

Excerpt

Atrial fibrillation (AF) initiation may be due to both abnormal focal activity and to reentry. AF frequently occurs under conditions associated with atrial dilatation (stretch) or vagal hyperactivity. Atrial stretch may contribute to focal arrhythmias by inducing afterdepolarizations and to reentrant arrhythmias by increasing the atrial surface, by shortening the refractory period and/or slowing the conduction velocity and by increasing spatial dispersion. Moreover vagal stimulation contributes to the maintenance of AF by decreasing the atrial refractory periods and increasing the inhomogeneity of refractoriness in the atria. Here we review recent findings showing that mechano-electrical feedback (MEF) may create a substrate for spontaneous initiation of vagal AF. We proposed that conduction slowing during acute atrial stretch may play a role in the genesis of cholinergic AF.