Temporal Dispersion of Atrial Activation causes Postoperative Atrial Fibrillation

Abstract

Background: Spatial dispersion of the atrial activation is one cause of post-operative atrial fibrillation (PoAF) after cardiac surgery. This study aimed to evaluate whether temporal dispersion of the atrial activation also causes PoAF after surgery in the clinical setting.

Methods: Nineteen patients were enrolled to evaluate their postoperative atrial activation from atrial pacing wires on the right atrium by 24h Holter electrocardiography for 5 days after cardiac surgery. No patients had taken any antiarrhythmic drugs including beta-blockers. The cycle length of 15 continuous atrial beats was measured at 4 time points: (i) more than 12 hours before the PoAF as a control, (ii) just before the PoAF onset, (iii) during PoAF, and (iv) just before the termination of PoAF. The inhomogeneity of the atrial activation was quantified by the variation coefficient of the cycle length of 15 atrial beats during each phase.

Results: The median inhomogeneity index of the atrial activation (first quartile, third quartile) was 0.102 (0.046, 0.136) in the control, 0.943 (0.582, 1.610) just before the PoAF onset (vs. control; p=0.009), 0.966 (0.631, 1.117) during PoAF, and 0.471 (0.138, 0.645) just before the termination of PoAF, respectively.

Conclusions: Dispersion of the atrial activation significantly increased just before the PoAF onset. Temporal dispersion of the atrial activation is one of the precursory variations of PoAF.