Background: Although refractoriness is a determinant of fibrillation, the relationship between atrial refractoriness and prediction of atrial fibrillation (AF) has not been studies in a large population-based cohort. We assessed the hypothesis that atrial refractoriness predicts development of AF. Methods: A total of 2949 subjects (male 1141, 43 ± 16 years) who underwent electrophysiological study and radiofrequency catheter ablation for PSVT from Jan 1986 to Dec 2010 were retrospectively reviewed. 2309 of 2949 subjects with concealed bypass tract (n=1157) or AV nodal reentrant tachycardia (n=1152) were finally enrolled in this study. Exclusion criteria was 1) a past history of AF or atrial flutter (AFL), 2) newly diagnosed AF or AFL at the time of admission for electrophysiology study, 3) WPW. Univariate and multivariate analyses were used to assess atrial effective refractory period (ERP) as a predictor of future development of AF.Results: During a follow up of 8.3 ± 5.4 years, 38 of 2345 (1.6%) developed AF. In univariate analysis, age >65 (HR 2.5, 95% CI 1.20-5.13, p=0.014), male (HR 1.41, 95% CI 0.33-1.06, p=0.07), atrial ERP (HR 1.02, 95% CI 1.01-1.03, p=0.002), baseline atrial ERP >220ms (HR 4.2, 95% CI 1.76-10.37, p=0.001), QRSd (HR 1.03, 95% CI 1.01-1.05, p=0.003), QRSd>120ms (HR 3.1, 95% CI 0.95-10.27, p=0.06) and VA block cycle length(BCL) (HR 1.01, 95% CI 1.01-1.02, p=0.011) were associated with the future development of AF. Baseline heart rate, AH interval, HV interval, AVBCL, AV nodal ERP, or tachycardia CL were not associated with AF development. In multivariate Cox-regression analysis, atrial ERP >220ms (adjusted HR 7.8, 95% CI 1.8-4-33.1, p=0.005), and QRS >120ms (adjusted HR 5.22, 95% CI 1.55-17.53, p=0.008) predicted high risk for developing future AF. When treated as a continuous variable, increased atrial ERP predicted increased risk for developing future AF (adjusted HR for 1-SD increase, 1.02, 95% CI 1.001-1.028, P=0.033).Conclusions: Atrial ERP may predict patients at increased risk for future development of AF.
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