Impact of pulsed field versus cryoballoon ablation on left atrial function and stiffness in paroxysmal atrial fibrillation

Background Catheter ablation is the cornerstone of invasive rhythm control strategies for atrial fibrillation(AF), with pulmonary vein isolation(PVI) remaining the key procedure. Emerging non-thermal energy sources, such as pulsed field ablation(PFA), have demonstrated safety and efficacy profile comparable to established thermal techniques like cryoablation(CBA), while potentially offering improved outcomes in AF recurrence. Left atrial(LA) function and stiffness are important predictors of AF recurrence; however, the effects of PFA on LA mechanics remain underexplored. Purpose The aim of this study was to compare the effect of CBA and PFA on echocardiographic indices of LA function and LA stiffness in patients with paroxysmal AF (PAF) undergoing PVI. Methods In this prospective, single-center study, patients undergoing first-time PVI for PAF were included. All individuals underwent transthoracic echocardiography at baseline(immediately prior to ablation) and at three months post-procedure. Parameters assessed included left ventricular ejection fraction(LVEF) by Simpson’s biplane method, LA diameter, LA volumes(LAV) by Simpson’s method, LA ejection fraction (LAEF, calculated as [LAVmax - LAVmin]/LAVmax), and LA reservoir(LASr), conduction(LAScd), and contraction(LASct) strain via 2D speckle-tracking echocardiography. The LA stiffness index(LASi) was calculated as the ratio of (E/e’)/LASr using mitral inflow peak velocities and tissue Doppler imaging of the lateral and medial mitral annulus. Baseline values and absolute changes in LA function parameters were compared between groups using the Mann–Whitney U test. Results A total of 36 patients were included [(CBA: N = 18, 47.8% male, mean age 62.44 ± 11.52 years, mean AF duration 7.26 ± 6.98 years, mean LA diameter 40.26 ± 4.14 mm) and (PFA: N = 18, 52.2% male, mean age 65.83 ± 11.02 years, mean AF duration 3.83 ± 4.31 years, mean LA diameter 42.11 ± 4.72 mm)]. Baseline characteristics did not differ significantly between groups. No statistically significant differences were observed at baseline in total LAEF (p = 0.103), LASr (p = 0.184), LAScd (p = 0.194), LASct (p = 0.289), or LASi (p = 0.569). At three months, the absolute changes in LA function and stiffness parameters did not differ significantly between CBA and PFA patients (Table 1). However, a non-significant trend was noted toward a greater reduction in LAEF and an increase in LASi in the CBA group compared to PFA (p = 0.11 and p = 0.13, respectively), suggesting a potentially more favorable effect of PFA to LA function. Conclusion Our findings suggest that PFA demonstrates a comparable and possibly more favorable profile to cryoablation in preserving left atrial function and stiffness during the blanking period. Larger multicenter studies are warranted to validate these results and assess long-term effects of both techniques on atrial mechanics and remodeling, which are important predictors of arrhythmia-free survival.