Predictive value of interatrial block for atrial fibrillation in elderly subjects enrolled in the PREDICTOR study.

AIMS: The principal aims of this prospective multicentre study were to relate the presence of interatrial block (IAB) with a late occurrence of atrial fibrillation (AF) and to demonstrate the independence of the IAB effect on risk of AF from structural cardiac alterations. METHODS: This prospective study was the follow-up of subjects included in the PREDICTOR cross-sectional population-based study. Subjects were divided into groups according to IAB status. Socio-demographic and health characteristic were collected during enrolment in the PREDICTOR along with ECGs, echocardiograms and NT-proBNP dosages. Follow up was performed on administrative data. The mean time of follow up was 6.6 years. RESULTS: 1626 subjects were included in the analysis. Four hundred-fifteen subjects out of 1626 (25.5%) had IAB. The survival analysis suggests an association between IAB alone and AF (HR = 1.50, p = 0.058) and, in normal-weight subjects, IAB strongly predicted AF indicating more than triple the risk (HR = 3.05; p = 0.002 95% CI: 1.51-6.18). The association seems to be independent of possible confounders such as history of IHD, left ventricular hypertrophy, CHA2DS2-VASc, left atrial dimension, or NT-proBNP dosage. CONCLUSION: Our analysis suggests that IAB is an electric condition that can increase the risk of AF independently of any structural cardiac alterations, at least in normal-weight subjects.