Correlation between the left atrial low-voltage area and the cardiac function improvement after catheter ablation for paroxysmal atrial fibrillation

Background The impact of the left atrial low-voltage area (LVA) on the cardiac function improvement following ablation for atrial fibrillation (AF) is unclear. Methods In 49 patients with paroxysmal AF who underwent ablation, the left ventricular stroke volume index (SVI) was repeatedly measured using an impedance cardiography until 6 months after ablation. We defined the cardiac function improvement as a 20% increase in the SVI. The LVA (the area with the voltage amplitude of <0.5 mV) was assessed before ablation. Results The reduced baseline SVI (<33 mL/m(2)) was observed in 18 (37%) patients. The SVI increased following ablation (from 36 +/- 5 to 39 +/- 6 mL/m(2), P < .001). We observed the cardiac function improvement in 14 (29%) patients. The LVA was smaller in patients with the improved cardiac function than in those without (8.3% +/- 5.2% vs 14.0% +/- 8.5%, P = .026). The multivariate analysis revealed that only the LVA was independently associated with the cardiac function improvement (odds ratio, 0.878; 95% confidence interval: 0.778-0.991, P = .036). Furthermore, LVAs of the anterior (7.9% +/- 7.6% vs 18.2% +/- 15.5%, P = .022), septal (12.0 +/- 7.3% vs 20.7% +/- 13.8%, P = .031), and roof walls (6.9% +/- 6.0% vs 16.9% +/- 15.2%, P = .022) were smaller in patients with the improved cardiac function than in those without. Conclusions The LVA was related to the cardiac function improvement following ablation in patients with paroxysmal AF.