Bilateral anterior carina low-temperature phenomenon during lattice-tip pulsed field ablation

Background The Sphere-9 lattice-tip pulsed field ablation (PFA) system uniquely enables real-time temperature monitoring during energy delivery. However, determinants of local temperature behavior during lattice-tip PFA remain poorly understood. Objectives To characterize segment-specific temperature behavior during lattice-tip PFA using system-defined contact-positive applications. Methods Thirty consecutive patients undergoing first-time atrial fibrillation ablation with the Sphere-9 system were retrospectively analyzed. Of 2,666 energy applications, 1,316 system-defined contact-positive pulmonary vein isolation–PFA applications were included. Pulmonary vein (PV) antral lesions were categorized into eight predefined segments for both the left and right PVs. Peak temperature, average temperature, and temperature rise (ΔPeak) were evaluated. As a sensitivity analysis, a linear mixed-effects model was performed. Results Significant segmental variation in temperature response was observed in both the left and right PVs. Peak temperature, average temperature, and ΔPeak differed significantly among segments in the left PV (all P<0.001) and right PV (all P<0.001). The anterior carina consistently exhibited a low-temperature profile across all evaluated metrics, whereas posterior segments demonstrated the highest temperatures. In linear mixed-effects models, posterior inferior, posterior carina, and posterior superior segments remained significantly higher in temperature than the anterior carina in both PVs. The anterior carina maintained a low-temperature profile during atrial fibrillation and sinus rhythm. Conclusion A reproducible bilateral anterior carina low-temperature phenomenon was observed during lattice-tip PFA under system-defined contact-positive conditions. These findings suggest that anatomical location may contribute to regional temperature behavior beyond system-defined contact display status alone.