Peak frequency mapping characteristics in patients with scar-related atypical atrial reentrant tachycardias; findings from a novel automated annotation algorithm to detect near field signals

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Abstract Background Atypical atrial tachycardias are commonly encountered rhythm disorders especially in patients with atrial low-voltage areas mainly due to previous catheter ablations or surgery. The peak frequency (PF) analysis of bipolar EGMs is a novel automated annotation tool which is mainly based on differentiation of near field signals from far field signals. Purpose In this study, we aimed to evaluate the association between PF analysis of voltage maps in low-voltage zones with the critical isthmus and termination sites of ATs. Methods In this retrospective analysis, we included a total of 36 patients (7 with right AT, 25 left AT, 4 biatrial). Omnipolar maps of RA and LA were created during AT using Ensite X Mapping system and HD-Grid catheter. Normal voltage is defined as ≥ 0.5 mV, borderline 0.1-0.5 mV and scar <0.1 mV. Only patients with acute termination of tachycardia with RF ablation were included. The sites within the 10 mm radius from the tachycardia termination site with RF were analysed in terms of voltage characteristics and PF analysis. Results The mean age of the study population was 53±15. Among 36 patients a total of 46 activation maps were created and 44 reentrant ATs were mapped. (24 (54.6%) ATs were macroreentry, 17 (38.6%) ATs were localized reentry and 3 ATs (6.8%) were dual-loop reentry). The low-voltage (LV) zones comprised 31.5±20.6% and 24.5±12.6% of total LA and RA, respectively. All AT termination sites using radiofrequency energy were located within the LV zones having high frequency activity using 250 Hz as the cut-off. The sensitivity of LV-NF zones to predict termination sites of re-entry was 97.2%. Conclusion The PF analysis of atrial substrate in the vicinity of the termination site of re-entrant ATs demonstrated high frequency signals within the low voltage zones. Therefore, addition of PF analysis with emphasis over voltage mapping may refine critical sites of reentry in LV regions.