Peak frequency can be effectively used to characterize scar in atrial fibrillation

Background

Characterizing atrial fibrillation (AF) substrate can guide ablation strategies.

Objective

A novel parameter, peak frequency (PF), was evaluated in its ability to characterize the substrate in AF.

Methods

Patients undergoing persistent AF ablation were included. Patients had omnipolar voltage (OV) and PF maps in AF and bipolar voltage (BV) maps in sinus rhythm (SR) at pacing intervals of 600 and 250 ms. PF was evaluated at sites of fixed remodeling (low voltage zones [LVZs] across all maps), functional remodeling (LVZs in AF OV and SR BV 250 ms maps) and non-LVZs. PF was defined as the highest frequency detected in the electrogram.

Results

In 40 patients, the average voltage in AF OV maps differed significantly from that in SR BV 600 ms maps (0.49±0.76 mV in AF OV vs 1.12±0.97 mV SR BV 600 ms; P<.001) but not SR BV 250 ms maps (0.49±0.76 mV in AF OV vs 0.52±0.84 mV SR BV 250 ms; P=.10). PFs of ≥244 and ≤214 Hz were predictive of non-LVZs (odds ratio [OR] 3.91; P<.001) with an area under the curve (AUC) of 0.71 and of fixed remodeling (OR 17.67; P<.001) with an AUC of 0.90, respectively. A PF between 215 and 236 Hz was predictive of functional remodeling (OR 2.83; 95% confidence interval 2.71–2.95; P<.001) with an AUC of 0.76. A majority of LVZs identified only in AF OV maps exhibited PF compatible with that seen in non-LVZs, suggesting that PF analysis can pinpoint potential overestimations of LVZs.

Conclusion

PF can effectively discern between sites of fixed remodeling, functional remodeling, and potential overestimations of LVZs. PF may thereby aid in better characterization of the substrate in AF.