Interplay of Probe Stability and Oscillation During Very-High-Power Short-Duration Ablation in Pulmonary Vein Isolation for Atrial Fibrillation

Background: Very-high-power-short-duration (vHPSD) ablation is increasingly adopted for pulmonary vein isolation (PVI) in atrial fibrillation (AF). While inadequate catheter–tissue contact is known to impair lesion formation under fixed 90 W/4-s setting, independent role of probe stability versus rapid oscillatory motion has not been quantitatively defined. Objective: To evaluate the independent and interactive effects of contact force (CF), positional stability (PS/PSV), and oscillation (OS/OSV) on lesion biophysics during vHPSD ablation in vivo. Methods: We retrospectively analyzed 80 consecutive AF patients undergoing PVI with a QDOT-MICRO catheter in vHPSD-mode (90 W/4-s, temperature-controlled). For each application (5198), CARTO3 trace data provided impedance, temperature, tip-to-tag distance, and CF (62.5Hz-sample). Stability parameters were defined as mean and variability of tip-to-tag distance (PS, PSV); oscillation parameters as mean and variability of tip velocity (OS, OSV). Primary endpoints were impedance drop (ID) and maximum temperature (Tmax). Mixed-effects regression models adjusted for baseline impedance, temperature, and CF; sensitivity analyses tested operator effect, and regional segments. Results: Minimum CF (p < 0.001) and oscillation parameters (OS p < 0.001, OSV p = 0.004) were the strongest predictors of ID and Tmax, whereas stability parameters had attenuated effects after adjustment. Interactions showed that increasing PSV and OSV reduced ID and Tmax, especially under higher CF. Regional analysis confirmed modestly lower signals in posterior/inferior segments, but oscillation remained the main determinant. Conclusion: Oscillation, more than positional stability, is the primary motion determinant of lesion efficacy in vHPSD. Minimizing oscillation rather than increasing CF is key to optimizing energy delivery. Prospective studies should assess whether reducing oscillation improves long-term outcomes.