Unified framework for the combined assessment of autonomic function and ectopic activity before post-operative atrial fibrillation

The mechanisms underlying the onset of postoperative atrial fibrillation (POAF) are still poorly understood. Enhanced atrial automaticity and alterations in autonomic tone following surgery have been suggested as critical predisposing factors. This paper proposes an unified framework for the combined analysis of ectopic activity and autonomic function preceding POAF. Atrial intervals series were automatically extracted from long-term atrial signal recordings in postoperative patients, and processed with an adaptive filter to separate normal from abnormal beats. Normal intervals were addressed to classical frequency-domain heart rate variability analysis, while ectopic beats were further processed to characterize their occurrence, coupling interval distribution and type. Preliminary application of the analysis showed concurrent changes in autonomic function and ectopic activity in the three hours preceding POAF onset. These results suggest the potential of the combined analysis to disclose interaction patterns between autonomic tone and automaticity leading to the onset of post-operative arrhythmias.