Different patterns of atrial activation in idiopathic atrial fibrillation:Simultaneous multisite atrial mapping in patients with paroxysmal and chronic atrial fibrillation

OBJECTIVES We aimed to evaluate: 1) the behavior of electrical activity sim ultaneously in different atrial regions during atrial fibrillation (AF); 2) the difference of atrial activation between paroxysmal and chronic AF; 3) the atrial refractoriness dispersion; and 4) the correlation between the ef fective refractory periods (ERPs) and the FF intervals. BACKGROUND Little data exist on the electrophysiologic characteristics of t he different atrial regions in patients with AF. A more detailed knowledge of the electrical activity during AF may provide further insights to improv e treatment of AF. METHODS Right and left atria were extensively mapped in 30 patients with id iopathic AF (18 paroxysmal and 12 chronic). In different atrial locations, we analyzed 1) the FF interval duration; and 2) the grade of organization a nd, in case of organized electrical activity, the direction of atrial activ ation. Furthermore, in patients with paroxysmal AF, we determined the atria l ERP, evaluated the ERP dispersion and assessed the presence of a correlat ion between the ERPs and the FF intervals. RESULTS In patients with chronic AF, we observed a shortening of the FF int ervals and a greater prevalence of disorganized activity in all the atrial sites examined. In patients with paroxysmal AF, a significant dispersion of refractoriness was observed. The right lateral wall showed longer FF inter vals and more organized atrial activity and, unexpectedly, the shortest mea n ERPs. In contrast, the septal area showed shorter FF intervals, greater d isorganization and the longest mean ERPs. CONCLUSIONS Electrical activity during AF showed a significant spatial inho mogeneity, which was more evident in patients with paroxysmal AF. The mean FF intervals did not correlate with the mean ERPs. (J Am Coll Cardiol 2001; 37:534-41) (C) 2001 by the American College of Cardiology.