Background:
High-density electroanatomical mapping is routinely used during catheter ablation of left atrial arrhythmias, including atrial fibrillation (AF) and atypical atrial flutter/atrial tachycardia (AFL/AT). Differences in mapping catheters and electroanatomical mapping platforms may influence procedural parameters and voltage-based substrate characterization. Comparative data on contemporary electroanatomical mapping platforms are limited.
Methods:
We retrospectively analyzed consecutive left atrial ablation procedures for AF and AFL/AT performed at a single center using either the Advisor HD Grid catheter in conjunction with the EnSite X mapping system (Abbott) or the PentaRay catheter in conjunction with the CARTO 3 mapping system (Biosense Webster). The primary endpoint was left atrial mapping time, defined as the time between the first and last acquired mapping point of the initial left atrial map. Secondary endpoints included procedure duration, left atrial dwell time, fluoroscopy time, fluoroscopy dose and voltage-based tissue characterization. Low voltage border-zone tissue was defined as bipolar voltages of 0.1–0.5 mV during sinus rhythm and 0.05–0.3 mV during AF/AFL mapping and expressed as a percentage of the total low-voltage substrate (≤0.5 mV and ≤0.3 mV, respectively).
Results:
A total of 436 procedures were included (EnSite X/Advisor HD Grid: n=123; CARTO 3/PentaRay: n=313). Baseline demographic characteristics, comorbidities, echocardiographic parameters, and arrhythmia indications were comparable between groups.
The primary endpoint, left atrial mapping time, was shorter in the CARTO 3/PentaRay group (13 [9–17] vs. 7.5 [IQR 2–12] min; p<0.001). In addition, procedure duration (90 [74–116] vs. 83 [68–100] min; p=0.004), left atrial dwell time (54 [45–69] vs. 46 [38–56] min; p<0.001), fluoroscopy time (8.32 [5–12] vs. 5.22 [4–7] min; p<0.001) and fluoroscopy dose (7.8 [5–13] vs. 5.5 [4–7] Gy·cm²; p<0.001) were lower in the CARTO 3/PentaRay group.
The percentage of acquired mapping points within the normal-voltage range did not differ between groups. However, the percentage of acquired border-zone voltage points within the low-voltage range was higher in CARTO 3/PentaRay-derived maps during sinus rhythm mapping (40% [35–49] vs. 59% [44–70]; p<0.001) and during AF/AFL mapping (62% [53–73] vs. 71% [56–87]; p<0.001), indicating differences in low-voltage substrate characterization between the two mapping systems.
Conclusions:
In this single-center real-world cohort of patients undergoing left atrial AF and AFL/AT ablation procedures, differences in procedural characteristics and voltage-based substrate characterization were observed between two electroanatomical mapping systems. While the proportion of acquired mapping points within the normal-voltage range was similar across platforms, differences were noted in the relative distribution of border-zone voltage within the low-voltage substrate regions. These findings suggest that mapping technology may influence not only procedural metrics but also the characterization of atrial substrate based on voltage mapping.
