['Renal impairment is associated with poor prognosis in the setting of atrial fibrillation (AF). While AF catheter ablation is an effective treatment modality for AF burden reduction and improvement of symptoms, changes in renal function after catheter ablation and their association with rhythm outcome have not been studied in a large contemporary AF ablation cohort.', 'To determine the association between CHADS2 and CHA2DS2-VASc scores and arrhythmia recurrences with changes in renal function following AF catheter ablation.', 'Estimated glomerular filtration rate (eGFR) was estimated using the Chronic Kidney Disease Epidemiology Collaboration equation at baseline and during follow-up in 783 patients undergoing de novo AF catheter ablation. Complete rhythm follow-up was achieved in 626 patients (80%) using serial 7-day Holter ECG.', 'The study population (n=783, 61±10\u2005years, 64% men, 57% paroxysmal AF) was followed up at median 20 (IQR 12-27)\u2005months. Baseline eGFR correlated with CHADS2 (β=-0.258, p<0.001) and CHA2DS2-VASc scores (β=-0.434, p<0.001). On multivariable analyses, eGFR changes were associated with AF recurrences (B=-0.136, p=0.014), CHADS2 (B=-0.062, p=0.035) and CHA2DS2-VASc scores (B=-0.057, p=0.003).'] Are changes in renal function after catheter ablation of atrial fibrillation associated with CHADS2 and CHA2DS2-VASc scores and arrhythmia recurrences?