Prolonged atrial refractoriness predicts the onset of atrial fibrillation: A 12-year follow-up study.

Background: Tissue refractoriness to conduction is a crucial electrophysiological factor in determining susceptibility to fibrillation. The relationship between atrial refractoriness and future onset of atrial fibrillation (AF) has not been well studied.

Objectives: We investigated whether atrial effective refractory period (AERP) was associated with AF occurrence in a relatively healthy population.

Methods: A total of 1308 patients with no overt structural heart diseases and no evidence of congestive heart failure who underwent electrophysiology studies for paroxysmal supraventricular tachycardia from January 1986 to January 2011 were included in the study (626 male, mean age 44 ± 16 years).

Results: AERP increased with increasing age. Over a mean follow-up of 12 years, 51 of 1308 subjects (3.9%) developed AF. In univariate analysis, baseline AERP ≥280 ms (hazard ratio [HR] 2.54, 95% confidence interval [CI] 1.27-5.07, P = .008) was strongly associated with new-onset AF. In multivariate Cox regression analysis, age (adjusted HR 1.40 per 10 years, 95% CI 1.15-1.70, P = .001) and AERP ≥280 ms (adjusted HR 2.08, 95% CI 1.03-4.21, P = .041) were associated with new-onset AF. Kaplan-Meier AF-free survival curves demonstrated that subjects with an AERP of ≥280 ms had significantly lower AF-free survival compared those with AERP of <280 ms.

Conclusions: AERP increases with age and AERP of ≥280 ms was predictive of patients at significantly increased future risk of developing AF.