Background: The ventricular response during atrial fibrillation (AF) has been shown to be modulated by the atrial rate. Objective: We hypothesized that the dynamics of ventricular response during persistent AF (pAF) correlates with the outcomes of catheter ablation.
Methods: In 40 consecutive pts (61±8 y, sustained AF 19±11 m), pulmonary vein isolation, defragmentation and linear ablations were performed within the left atrium (LA) until pAF termination or cardioversion. Recurrence quantification analysis was performed on RR-interval time series extracted from 5-min ECG recorded before ablation (BL) and at the end of LA ablation (end_ABL). Percentage of recurring points (RP) and percentage of determinism (DET) were computed as measures of the temporal regularity of RR-intervals. AF recurrence during follow-up (FU) was defined as any atrial arrhythmia > 30 sec. Results: pAF was terminated within the LA in 70% (28/40, LT) of the pts, while 30% (12/40, NLT) were not. Over a mean FU of 34±14 months, recurrence occurred in 100% of NLT pts and in 71% of LT pts (20/28, LT_Rec), while 29% of LT pts (8/28, LT_SR) remained in sinus rhythm after a single procedure. NLT pts, all with recurrence at FU, displayed significantly lower RP and DET values, indicative of a higher complexity of RR-intervals both at BL and at end_ABL than pts with a successful procedure. Higher DET and RP values indicative of decreased complexity of RR-intervals at end_ABL were associated with AF termination and reduced AF recurrence at FU. Conclusion: Complexity measures of ventricular response in pAF appear as promising parameters of catheter ablation outcomes.