Dispersion of atrial repolarization in patients with paroxysmal atrial fibrillation

To study the role of the dispersion of atrial repolarization (DAR) in the g enesis of atrial fibrillation (AF), monophasic action potentials (MAP) were recorded simultaneously from a catheter at the high lateral right atrium ( HLRA) and a catheter moving around the high, middle and low lateral right a trium (RA) the high. anterior and posterior septal RA and the RA appendage in 15 patients with paroxysmal AF and 15 patients with atrioventricular nod al re-entry tachycardia (AVNRT) or concealed Wolff-Parkinson-White syndrome (WPW) without history of AF. After recordings during sinus rhythm (SR), MA Ps were recorded during programmed stimulation (PS) via the HLRA catheter a t a drive cycle length (CL) of 500 ms. Thus. MAPs were recorded simultaneou sly from 2 sites at a time and sequentially from 4 to 12 sites during SR, d rive pacing and PS. Taking the MAP at the HLRA as reference, the dispersion of repolarization time (dispersion of RT) and its two components, the disp ersions of activation time (dispersion of AT) and MAP duration (dispersion of MAP duration) among the 4 to 12 sites were calculated and taken as param eters of DAR. Results During SR and PS. the maximal dispersion of RT was significantly gr eater in AF than in control patients, 113 +/- 49ms vs 50 +/- 28 ms (P < 0.0 01) and 114 +/- 56 vs 70 +/- 43 ms (P < 0.05) respectively. The increased d ispersion or RT in the AF group was caused by increases in both dispersion of MAP duration and dispersion of AT. Conclusion During SR and PS, DAR increased in patients with paroxysmal AF d ue to increases in dispersion of MAP duration and dispersion of AT, which s uggests the involvement of both repolarization and conduction disturbances in the development or paroxysmal AF. (C) 2001 The European Society of Cardi ology.