Comparison of Far-Field and Peak Frequency Electrogram Characteristics at the Earliest Activation Sites during Idiopathic Ventricular Arrhythmias: A novel index to predict ablation success

Evaluating the peak frequency electrograms has the potential to differentiate near-field from far-field components. This study examined how peak frequency analyses of electrograms preceding idiopathic ventricular arrhythmias (VAs) impact catheter ablation outcomes. A retrospective analysis was conducted on 111 VAs from 104 patients. Electrograms at the earliest activation site, detected using high-density activation maps, were analyzed to assess the association with successful elimination following a single radiofrequency delivery. In outflow tract VAs (n=77), the first deflection timing was similar for VAs with and without successful elimination. The peak frequency timing was earlier (RVOT: -21 ms [-32--16 ms] vs. -11 ms [-20-0 ms], p=0.002, LVOT: -26 ms [-33--4 ms] vs. 0 ms [-6-10 ms], p=0.005) and the difference between the first deflection and peak frequency timing (delta F-P) shorter (RVOT: 7 ms [5-13 ms] vs. 17 ms [11-24 ms], p<0.001, LVOT: 10 ms [6-19 ms] vs. 22 ms [20-27 ms], p=0.001) for VAs with a successful elimination than for those without. The delta F-P correlated with the time to elimination of outflow tract VAs (p=0.01, r= 0.45). None of the outflow tract VAs with delta F-P >22 ms achieved successful elimination. For non-outflow tract VAs (n=34), no parameters were associated with successful elimination. The first component of the EGM at the earliest activation site may reflect a far-field recording from the site of origin of idiopathic VAs. A novel delta F-P electrogram index may predict quick successful endocardial ablation of outflow tract VAs.