Ventricular fibrillation risk factors in over one thousand patients with accessory pathways

Abstract

Background: Published data concerning risk factors of VF in WPW patients are inconsistent or contradictory.

Methods and results: We included 1007 patient (pts) (mean age 35 years; 45% female) with an accessory pathway (AP) referred for non pharmacological treatment. Group 1 consisted of 56 pts (42M, aged 34 ± 15 yrs) with an AP and documented VF and Group 2-951 pts (513M, aged 35 ± 15 yrs) with an AP and without VF. Univariate predictors of VF were: overt pre-excitation, male gender, multiple AP, large AP. Multivariate predictors were: overt pre-excitation, male gender and MAP. The mean shortest pre-excited RR interval during AF was significantly shorter in Group 1: 205 ± 27 vs. 243 ± 64, P=0.019. VF as an end point of the first arrhythmia episode (AVRT or AF) was observed in 20 pts (15M, 5F). Primary VF (no documented arrhythmia prior to aborted SCD) occurred in 16 pts (13M, 3F). The mean age of primary VF pts was significantly lower than of pts with history of AVRT or AVRT and/or AF (24.5 vs. 36.5 vs. 38 yrs., P<0.005 and P=0.002, respectively). Age at VF occurrence shows a bi-modal distribution with peak occurrences in the 2-nd/3-rd and 5-th decades.

Conclusion: In patients with an accessory pathway, overt pre-excitation, male gender and multiple AP constitute independent risk factors of VF episodes. Young patients in the 2-nd/3-rd and older patients in the 5-th decade might be at higher risk of VF occurrence.