Left Atrial Function After Radiofrequency Catheter Ablation of Atrial Fibrillation　– Can Pre-Ablation Function Predict Contractile Improvement During Follow-up? –

BACKGROUND: Data are lacking on the effect of radiofrequency catheter ablation (RFCA) on atrial function. The aim of this study was to determine a cut-off of pre-ablation left atrial (LA) function in order to predict atrial functional recovery after RFCA. METHODS AND RESULTS: A total of 64 atrial fibrillation (AF) patients who underwent RFCA were enrolled (age, 59.05±12.09 years; 36% persistent AF; LA volume 37.8±13.6 ml/m(2)). LA emptying fraction (LAEF), LA active fraction (LAAEF), LA passive emptying fraction (LAPEF) and LA expansion index (LAEI) were evaluated in sinus rhythm before and 48 h, 15 days, 1, 2, 3 and 9 months after ablation. LA function improvement was defined as any positive increase in LAEF compared with baseline. On univariate and multivariate analysis only baseline atrial function proved to be an independent predictor of LA function improvement after ablation (P=0.002; OR=0.001; 95% CI: 0.000-0.099). On receiver operating characteristic analysis (AUC=0.70), cut-off for baseline LAEF was 40%. At 9 months, patients with LAEF <40% had significant improvement in atrial performance (LAEF, P=0.01; LAAEF, P=0.036; LAEI, P=0.004); a significant negative correlation between baseline LAEF and LA function improvement was observed (r=-0.62; 95% CI: -0.83 to -0.26; P(r=0)<0.002). CONCLUSIONS: Baseline LAEF is an independent predictor of LA function recovery after RFCA. The beneficial effect of AF ablation is most evident in patients with LAEF<40%.