Comparison of additional ablation of spatio-temporal dispersion electrograms and low voltage area beyond pulmonary vein isolation in patients with persistent atrial fibrillation

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Abstract Backgrounds Although strategies beyond extensive pulmonary vein isolation (EPVI) including low voltage zone (LVZ) ablation in patients with persistent atrial fibrillation (AF) have not yet been established, recent research showed that ablation targeting spatio-temporal dispersion electrograms (STDE) could achieve high AF-free survival. We hypothesized that EPVI plus STDE approach could reduce AF recurrence after catheter ablation of persistent AF. Purpose The purpose of this study is to assess the AF recurrence after the ablation in different two strategies. Methods We prospectively enrolled consecutive patients with persistent AF undergoing their first catheter ablation at our institution during July 2018 to March 2021. The ablation strategy was divided into 2 groups: 1) EPVI plus LVZ and 2) EPVI plus STDE ablation. STDE was defined as clusters of fractionated electrograms that displayed interelectrode time and space dispersion at a minimum of three adjacent bipolar electrodes such that activation spread over all the cycle length of AF. The definition of LVZ was bipolar amplitude of <0.5mV. Posterior wall isolation was performed if STDE or LVZ were broadly present in posterior wall. The primary endpoint was defined as AF recurrence after the ablation. The blanking period of 3 months was applied. Results Out of 138 patients (66±11 years, 108 men), 64 patients underwent EPVI plus LVZ and 74 EPVI plus STDE ablation. There was no difference in median AF duration (8 [interquartile range (IQR) 4-13] months vs. 12 [IQR 5-22] months; p=0.129) and left atrial volume (151 [IQR 115-168] ml vs. 151 [IQR 127-175] ml; p=0.239) between the two groups. The prevalence of concomitant hypertension (47% vs. 67%; p=0.024) and diabetes mellitus (24% vs. 42%; p=0.027) was lower in the STDE group than in the LVZ group. Posterior wall isolation was performed more frequently in the STDE group than in the LVZ group (38% vs. 19%; p=0.015). At 1 year follow-up, the STDE group achieved higher AF-free rate than the LVZ group (84% [95% confidence interval (CI), 73-91%] vs. 64% [95% CI 52-76%]; P=0.017). Multivariate Cox regression analysis demonstrated that not only AF duration (hazard ratio [HR] 1.03, 95% CI 1.01–1.04; p<0.001), and left atrial volume (HR 1.10, 95% CI 1.02–1.19; p=0.011) but also STDE ablation (HR 0.33, 95% CI 0.14-0.77%, p=0.010) were independently associated with AF recurrence. Conclusions Ablation guided by STDE in addition to EPVI may be a useful treatment strategy for persistent AF.