Comparison of spatiotemporal dispersion electrogram ablation and low voltage zone ablation in patients with persistent atrial fibrillation
Y Kaneko, Y Naruse, Y Tokonami, K Ito, M Sano, Y MaekawaAbstract
Background
Pulmonary vein isolation (PVI) alone was less effective for patients with persistent atrial fibrillation (AF) compared to those with paroxysmal AF. Although the TAILORED AF trial demonstrated the efficacy of spatio-temporal dispersion electrogram (STDE) ablation as additional treatment for PVI, comparisons between STDE and low-voltage zone (LVZ) remain unclear. Furthermore, differences in characteristics as AF substrate detected by these two methods are also unclear.
Purpose
We aim to assess the AF recurrence after the ablation in different two strategies and the characteristics of AF substrate detected by STDE.
Methods
A total of 107 consecutive patients (67±11 years, 79 men) who underwent initial catheter ablation of persistent AF at our institution between 2018 and 2021 were prospectively included. The ablation strategy was divided into 2 groups: 1) PVI plus LVZ ablation until 2019 (n=53) and 2) PVI plus STDE from 2019 (n=54). STDE was defined as clusters of fractionated electrograms with time and space dispersion by using multipolar mapping catheter (Advisor HD grid or PENTARAY catheter). LVZ was defined as bipolar amplitude of <0.5mV during sinus or atrial pacing rhythm. When the targets were located on the LA posterior wall, posterior wall isolation was performed. And the targets on other sites were ablated focally. The AF recurrence was evaluated up to 24 months after applying the blanking period of three months.
Results
The median AF duration was longer in the STDE group (14 [ (IQR) 6–36] months vs. 10 [4–13] months; p=0.027). There was no significant difference in left atrial volume (156.5 [132.7–174.8] ml vs. 151.3 [114.6–166.6] ml; p=0.127). Additional ablation beyond PVI was performed more frequently in PVI plus STDE group (69.8% vs. 40.7%; p=0.004). At two years follow-up, the STDE group achieved a higher AF-free rate than the LVZ group (76.3% [95% confidence interval (CI) 62.1–85.8%] vs. 58.4% [95% CI 43.8–70.4%]; P=0.027). Multivariate Cox regression analysis demonstrated that not only AF duration and left atrial volume but also STDE ablation (HR 0.29, 95% CI 0.12–0.66, p=0.004) were independently associated with AF recurrence. STDE in the left atrium (LA) was identified in 37 patients (69.8%). As the distribution of STDE, the LA posterior wall (n=26) and the LA anterior wall (n=25) were common locations for STDE. The additional analysis about bipolar voltage of STDE in 28 cases (981 points) showed that the average voltage of all STDE points during AF was 0.91 ± 0.61 mV. Bipolar voltage of <0.2mV, 0.2–0.5mV, and >0.5mV was observed in 68 (6.9%), 229 (23.3%), and 684 (69.7%) points, respectively.
Conclusion
Substrates detected by STDE tended to exhibit relatively preserved voltage and were frequently observed not only in the posterior wall but also in the anterior wall. STDE ablation beyond PVI can be effective for persistent AF.