Prognostic implication of left atrial sphericity in atrial fibrillation patients undergoing radiofrequency catheter ablation

BACKGROUND: Left atrial (LA) sphericity can predict recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA). We sought to reconfirm the prognostic role of atrial sphericity after RFCA of atrial fibrillation (AF), assess any relationship between the atrial pressure and sphericity, and determine the characteristics of the patients for whom atrial sphericity was most highly predictive. METHODS: All 148 nonvalvular AF patients (57 ± 11 years, 121 men, 95 paroxysmal AF PaAF) who underwent RFCA were enrolled. The LA volume (LAV) was determined and LA sphericity assessed from three-dimensional computed tomographic images. The preprocedural mean LA pressure (mLAP) was measured. RESULTS: After a 3-month blanking period, AF/atrial tachycardia (AT) recurrences within 1 year were documented in 38 patients (26%). Patients with recurrence had a greater LAV (124 ± 35 mL vs 151 ± 45 mL, P < 0.001) and LA sphericity (0.669 ± 0.040 vs 0.684 ± 0.038, P = 0.041). In patients with smaller LAs (LAV < 125 mL), LA sphericity predicted AF/AT recurrences (odds ratio OR: 1.030 for each 0.001 increase, 95% confidence interval CI: 1.008-1.053, P = 0.007), whereas the LAV did not. In patients with larger LAs (LAV ≥ 125 mL), the LAV could predict recurrence (OR: 1.021, 95% CI: 1.001-1.041, P = 0.036), while the LA sphericity could not. The LA sphericity and mLAP are linearly correlated (r = 0.345, P < 0.022) in persistent AF, but not PaAF. CONCLUSIONS: LA spherical change precedes severe LA enlargement in AF. It predicts 1-year AF/AT recurrence after RFCA and is more important than the LA size in patients with less severe LA enlargement.