Impact of cryoablation versus pulsed field ablation on left atrial elasticity assessed by pressure-volume loops in paroxysmal atrial fibrillation

Introduction Cryoballoon ablation (CBA) is an established thermal method for pulmonary vein isolation (PVI), while in recent years, pulsed field ablation (PFA) -a non-thermal energy source- has shown promising results in improving clinical outcomes. However, the effect of these two techniques on left atrial elasticity has not been thoroughly investigated. Purpose The aim of this study was to evaluate acute changes in LA elasticity using pressure-volume (PV) loop analysis following paroxysmal atrial fibrillation (PAF) ablation, and to compare the mechanical effects of cryoballoon and pulsed field ablation on the LA. Methods In this prospective single-center study, consecutive adults undergoing first-time PVI for PAF were included. Patients underwent either CBA using a cryoballoon system with overinflation capability(cryodosing based on time-to-isolation interval) or PFA using a pentaspline catheter system capable of assuming flower and basket configurations. LA pressure was measured after transseptal puncture, before ablation, and at the end of the procedure. LA volumes were assessed by Simpson’s method on transthoracic echocardiography before and after ablation. PV data from the ascending limb of the PV-curve were fitted to the exponential function P = b × ea·V. The stiffness constant of the passive elastic chamber (a), which quantifies left atrial stiffness, and the elasticity constant (b), representing baseline pressure conditions of the left atrium, were calculated with the least squares method. Results A total of 38 patients were included (CBA: n=18, 60% male, mean age: 62.6± 10.99, mean AF duration: 7.27± 6.98 years, and PFA: n=20, 60% male, mean age: 61.8±9.12, mean AF duration: 3.83 ± 4.31 years). Baseline characteristics did not differ between the two groups. CBA resulted in a significant reduction in the elastic constant (b) (Δb CBA -6.38×10−2mmHg, p-value: 0.034), and a mild but non-significant increase in stiffness (a) (Δα CBA: 1.32×10−2ml-1, p-value: 0.204). Patients in the PFA group exhibited no significant alterations in either parameter (Table 1). Conclusions Both CBA and PFA demonstrated comparable effects on left atrial mechanical properties in the acute post-ablation setting, with no significant changes in the passive stiffness constant (a) after either procedure. The mild reduction in the elastic constant (b) with CBA did not alter overall atrial elasticity, suggesting that both modalities preserve left atrial compliance acutely. Larger multicenter studies are needed to confirm these results and to assess the long-term impact of the two energy modalities on left atrial elasticity, diastolic function, and ablation outcomes.