The Difference of Clinical and Electrophysiological Characteristics of Wolff Parkinson White Syndrome with Atrial Fibrillation and with Only Atrioventricular Reentry Tachycardia

Introduction: The reason for high incidence of atrial fibrillation(AF) in the WPW syndrome is not yet clearly understood. Methods: This was a retrospective study of patients with WPW referred for accessory pathway (AP) ablation due to clinical documented AVRT and/or Af or unknown cause of palpitation from 1998 to 2011. Standard electrophysiological study (EPS) were performed to induce AVRT or Af. We compared electrophysiological and clinical characteristics between the patients with Af or Af/AVRT(group1), and the ones with only AVRT (group2). Results: EPS was performed among 797 (528 male) patients with WPW syndrome. The patients with AVRT, AVRT/Af, and Af were 611 (76.7%), 77 (9.7%), and 93 (11.7%), respectively. Sixteen patients (2.0%) was not induced any tachycardia. Group1 were older than group2 (42±14 vs 37±16). The frequency of multiple accessory pathway was similar between both group. Effective refractive period (ERP) of atrium and ventriculoatial block cycle length (BCL) of AP were significant longer in group1 than group2. Anterograde ERP and Atrioventricular BCL of AP were significantly shorter in group1 than group2. Conclusion: Shortened anterograde ERP of AP may suggest one mechanisms of Af development in patients with WPW syndrome. But atrial ERP may have minor role of that.