Double atrial potentials in left‐sided accessory pathways are associated with paroxysmal atrial fibrillation
The incidence of atrial fibrillation (AF) in patients with Wolff‐Parkinson‐White (WPW) syndrome ranges between 10% and 30%.1 The reasons of this phenomenon in subjects without structural heart disease and in younger age are not clearly determined. It was shown that the occurrence of atrioventricular accessory pathway (AP) contributed to more frequent episodes of AF.1 Shorter refractory period of AP and electrophysiological (EP) properties of the atria1 also predispose to AF. Konoe et al.5 stated that the presence of fragmented atrial potentials in WPW patients also promotes AF episodes. Moreover, it was confirmed that atrioventricular reentrant tachycardia (AVRT) increases the incidence of AF in WPW syndrome.1 In addition to the bundle of Bachmann that connects both, the right (RA) and left atrium (LA) in their anterior aspects, the results of experimental studies suggested an alternative connection between the RA and LA.7 Potential electrical connections of the coronary sinus (CS) and LA, but distinct from the interatrial septum, were suggested after cardiac surgery where muscular connections within the CS were removed by means of cryoablation.9 Such a treatment resulted in a reduction of AF burden. The anatomical studies showed the presence of atrial muscle fibers of different spatial arrangement surrounding the CS, which connect the CS and LA.10 In addition, the splitting of atrial potential (double atrial potential, DP) was observed in the CS recordings during AVRT.12 The conclusion was made that the muscular connection between the LA, CS, and pulmonary veins can be identified by atrial signal separation in the CS recordings.12
The study aimed to evaluate the presence of DP in the intracardiac recordings from the CS during the AVRT in subjects with left‐sided AP (AP‐L) as well as assessment of incidence of AF episodes in patients with DP.