ANATOMICAL DISTRIBUTION, CONDUCTION PROPE RTIES, AND MODE OF RECURRENCE AFTER ABLATION OF MULTIPLE COMPARED TO SINGLE ACCESSORY PATHWAYS

In 1076 consecutive patients referred for radiofrequency current cathe ter ablation, the anatomical distribution and conduction properties of accessory pathways (APs) as well as the mode of recurrence after abla tion were retrospectively analyzed and compared in patients with multi ple and single APs. Except for 17 patients with Ebstein's anomaly, the prevalence of patients of multiple APs in this cohort was 5.4 %. Pati ents with multiple APs, as opposed to patients with a single AP, had s ignificantly more often APs located on the right free wall (23 % versu s 10 %) and - since the prevalence of septal APs was identical in both groups - less frequently APs located on the left free wall (44 % vers us 56 %). Also, concealed APs were significantly more often encountere d in patients with multiple APs (45 % versus 24 %). Recurrence of cond uction across an AP which had presumably been ablated was observed in both groups with statistically equal incidence of < 5 %. In 11 patient s with multiple APs, the additional AP was only found at the repeat se ssion. These ''new'' APs were mostly concealed (9 out of 11) and neces sitated an intervention predominantly late after the initial ablation session. Intermittent concealed conduction appears to be a likely expl anation for this phenomenon. Patients with multiple APs exhibit a high er incidence of right free-wall and concealed APs, yet they stand the same, approximately 95 %, chance of cure as do patients with a single AP. Nearly 25 % percent of repeat sessions in patients initially thoug ht to have a single AP are caused by the late manifestation of an addi tional AP.