Introduction: We aimed to assess reverse left atrial (LA) remodeling at 6 months aft er pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF) and to identify the most relevant parameter of reverse left atrial remodeling. Methods: LA size was assessed by echocardiography: antero-posterior diameter (LAD), left atrial area in apical 4 and 2 chamber (A4c, A2c), left atrium volume by linear dimension (LAV1) and by biplane formula  (LAV2) and by computer-tomography (LAV3) in 78 consecutive patients with mean age was 57.41 ± 8.05 years; 60 out of those were with PAF less than 24 ore (76.9%) and 18 with PAF less than 7 days (23.1%). All echocardiographic and computer tomographic evaluations were made within 4 weeks before ablation and at 6 months aft er PVI by the same operators. Circumferential or segmental PVI was performed by radiofrequency  (RF) in 58 patients (74.4%), and by cryotherapy in 18 patients (23.1%). Antral PVI was obtained at 35 W and minus 40°, respectively. Results: At 6 months 53 patients (67.9%) were in stable  sinus rhythm, 18 out of those on antiarrhythmic medication. A redo procedure was made in 8 patients (10.3%), which improved the maintenance of stable sinus rhythm at 61 patients (78.3%). At 6 months all echocardiographic parameters for LA size assessing
decreased statistically significant as follow: LAD from 42.06 ± 6.88 mm to 39.80 ± 8.29 (P 0.05), A4c from  26.02 ± 6.90 cm² to 23.01 ± 6.21 cm² (P 0.003), A2c from 25.92 ± 7.52 cm² to 24.22 ± 5.55 cm² (P 0.011), LAV1 from 47.08 ± 9.68 ml to 42.60 ± 12.30 ml (P 0.001), and LAV2 from 48.90 ± 23.36 ml to 43.58 ± 17.09 ml (P 0.026). Th e LAV3 measured by computertomography
remained unchanged from 41.12 ± 19.33 ml to 41.86 ± 10.85 ml (P 0.807).

Conclusions: The maintenance of stable sinus rhythm aft er paroxysmal atrial fibrillation ablation determined a significant reverse left atrial remodeling, irrespective of echocardiographic parameters used in left atrial size assessment at six months after ablation procedure. The most relevant echocardiographic parameter seems to be LA apical 4 chamber area and indexed left atrial volume by linear formula. The assessment of left atrial volume by computer tomography seems to be less predictable to follow reverse left atrial remodeling.