Abstract 13033: Abnormal P-Wave Axis is Associated With an Increased Risk of Sudden Cardiac Death: The Atherosclerosis Risk In Communities (ARIC) Study

Abstract

Introduction: Abnormal P-wave axis (aPWA) has been linked to all-cause mortality and incident atrial fibrillation (AF). The relationship between aPWA and sudden cardiac death (SCD), however, has not been defined. Hypothesis: We hypothesized that aPWA is independently associated with SCD and tested our hypothesis in the ARIC study, a community-based prospective cohort study. Methods: We included 15,381 participants (age 54.2 ± 5.7 years, 55% women, 26.4% blacks) who attended the baseline visit (1987-89) and with complete ECG data. aPWA was defined as any value outside 0-75 degrees using 12-lead ECGs obtained during the baseline exam. SCD was physician-adjudicated and defined as a sudden, pulseless condition in a previously stable individual without evidence of a non-cardiac cause of death. Cox regression was used to compute hazard ratios and 95% confidence intervals for the association of aPWA with SCD. Results: At baseline, there were 1,275 participants with aPWA. During a mean follow-up of 13.1 years (1987-2001), 272 SCDs were identified from coronary heart disease deaths. aPWA was associated with a 1.49-fold (95% CI, 1.03-2.15) increased risk of SCD independent of traditional SCD risk factors. However, after adjustment for time-dependent AF, the association of aPWA with SCD was attenuated (Table). Conclusions: aPWA is associated with an increased risk of SCD in the general population. This association, however, is likely mediated by AF; the latter we recently reported to be a risk factor for SCD. aPWA is associated with an increased risk of SCD in the general population. This association, however, is likely mediated by AF; the latter we recently reported to be a risk factor for SCD.