Role of Octaspline Multielectrode Catheter and Unipolar Reference Location for Premature Ventricular Contraction Ablation

BACKGROUND: An accurate local activation time (LAT) map is essential during premature ventricular contraction (PVC) ablation. The aim of this study was to evaluate whether the use of a novel octaspline multielectrode catheter, with and without the use of a catheter-embedded unipolar reference, improves LAT mapping during PVC ablation compared to a pre-existing pentaspline mapping catheter. METHODS: This study prospectively assessed 10 consecutive patients referred for PVC ablation from January to June 2023. Three 12-min LAT maps were performed in each patient using three different strategies: pentaspline catheter + unipolar reference in the inferior vena cava (IVC) versus octaspline catheter + unipolar in the IVC versus octaspline catheter + unipolar embedded in the mapping catheter. Acute procedural and midterm endpoints were assessed. RESULTS: The use of an octaspline catheter increased the number of total LAT points (1010 ± 451 vs. 397 ± 213, p = 0.001), LAT points near the successful RF ablation site (118 ± 105 vs. 21 ± 19, p = 0.010) and electrograms (EGM) per PVC (23 ± 21 vs. 7 ± 3, p = 0.032), while reducing mapping duration (65 ± 41 EGM/min vs. 21 ± 8 EGM/min, p = 0.003). However, signal resolution was not superior to that obtained with the pentaspline catheter, with similar bipolar (p = 0.505) and unipolar (p = 0.176) voltages, an increased bipolar signal duration (p = 0.003) and a reduction in the unipolar signal duration (p = 0.013). Use of a catheter-embedded unipolar reference led to shorter unipolar signal duration (76 ± 34 ms vs. 142 ± 29 ms, p < 0.001), and provided an earlier unipolar signal deflection to QRS onset (-24 ± 16 ms vs. -19 ± 11 ms, p = 0.006) and earlier -dV/dT signal annotation (-12 ± 10 ms vs. -7 ± 9 ms, p < 0.001). This subsequently led to a shorter distance from the earliest LAT to successful RF site (p = 0.014). No significant differences between multielectrode mapping catheters were seen regarding catheter-induced ectopy rate (p = 0.703). CONCLUSIONS: The use of an octaspline catheter combined with an embedded unipolar reference may associate with faster, more detailed and accurate activation mapping in the setting of PVC ablation.