Electrical remodeling of the atria associated with paroxysmal and chronic atrial flutter

Atrial electrical remodeling may be important for the initiation and perpetuation of atrial arrhythmias. Whether paroxysmal atrial flutter (AFL) and chronic AFL cause electrical remodeling of the atria has not been conclusively determined. Before radiofrequency ablation of paroxysmal AFL, 15 patients in sinus rhythm were evaluated under autonomic blockade. Lateral right atrial (LRA) effective refractory periods (ERPs) at 600 and 450 ms were measured before and at 1-minute intervals for 10 minutes after spontaneous or pace termination of a 5- to 10-minute period of induced AFL. In 10 patients with chronic AFL, LRA, septal, and coronary sinus (CS) ERPs and corrected sinus node recovery times (cSNRTs) at 600 and 450 ms were measured under autonomic blockade 15 minutes, 30 minutes, and 3 weeks after termination of chronic AFL by ablation. In the paroxysmal AFL group, LRA ERPs decreased by 18% at 600 ms and 12% at 450 ms (P: