BackgroundThe slow-pathway potential is difficult to annotate because it is buried within the atrial potential. Omnipolar technology Near Field (OTNF) in Ensite X can automatically annotate the peak frequency potential associated with acquired intracardiac electrograms. ObjectiveThis study aimed to visualize the junction between the transitional cells and the slow pathway using a peak frequency map with OTNF and evaluate whether the high-frequency site around the tricuspid annulus (TA) is an effective target for slow pathway ablation. MethodsThis prospective observational study enrolled 37 patients with typical atrioventricular nodal re-entrant tachycardia. Patients underwent slow pathway ablation using peak frequency map (n = 17) and the conventional approach based on anatomical and electrophysiological findings (n = 20). ResultsHigh-frequency sites were distributed at the TA side of 4–5 o’clock in all peak frequency map-guided patients. The distance to His bundle from successful ablation site was farther (24.0 ± 4.8 vs. 12.7 ± 4.0 mm, p < 0.0001), junctional rhythm was slower (88 ± 17 vs. 115 ± 12 bpm, p < 0.0001), time to junctional rhythm after radiofrequency application was shorter (3.4 ± 1.4 vs. 8.2 ± 4.6 sec, p < 0.0001), and elimination rate of jump up (71 vs. 30%, p = 0.02) was higher in the peak frequency map-guided group. ConclusionThe high-frequency site of the TA at 4–5 o’clock in the peak frequency map could be a novel target of slow pathway ablation with high safety, efficiency, and efficacy.