Peak frequency drop: a novel intraprocedural parameter predicting acute conduction gaps post-pulmonary vein isolation.

Background: The identification of potential gap sites after pulmonary vein isolation (PVI) and prevention of these warning points during ablation are crucial. We evaluated the changes in peak frequency (PF) on electrograms and examined the relationship between its value and the residual pulmonary vein (PV) gap after PVI.

Methods: We included patients with a PV gap after PVI with a power setting of 50 W using a novel irrigated-tip catheter (TactiFlex, Abbott). The PF on bipolar electrograms in the ablation catheter was recorded immediately before and after ablation at all available ablation points, using Omnipolar technology near field. We compared the pre- and post-PF values, changes in PF, contact force, and impedance drop between points with and without a PV gap following PVI.

Results: A total of 695 ablation points in 13 patients were analyzed. There were 19 and 676 points with and without the PV gap, respectively. The PV gap group demonstrated significantly lower PF drop and contact force (-14 ± 43 Hz vs. 61 ± 57 Hz, p < 0.001; and 8 [7-10] g vs. 10 [4-14] g, p = 0.039), and higher post-PF (226 ± 49 Hz vs. 176 ± 47 Hz, p < 0.001) than in the non-PV gap group. The PF drop had the highest area under the curve of 0.878 (95% confidence interval: 0.791-0.964) on receiver operating characteristic curve analysis for predicting the PV gap, with a cutoff value of 10.5 Hz (sensitivity, 81.8%; specificity, 89.5%).

Conclusion: PF drop during PVI is a useful parameter for predicting the non-PV gap with a high probability.