Introduction Left anterior line (LAL) has been reported to be more efficient than mitral isthmus line for catheter ablation of chronic atrial fibrillation (AF). However, LAL resulted in left atrial (LA) anterolateral conduction delay and might affect LA contractility. The aim of this study was to investigate whether LAL decrease LA contractility. Methods This study included 15 patients (60% men, mean age 56.8 짹 5.8 years) who underwent catheter ablation for persistent AF. Ablation procedure included antral isolation of pulmonary veins, roof line, LAL and right atrial isthmus block. LAL block was confirmed by bidirectional pacing. Transthoracic and transesophageal echocardiography with Doppler tissue imaging was performed in sinus rhythm before and after the ablation. We compared variables as follows; (1) E/A ratio of the mitral flow velocity, (2) ratio of early mitral inflow and mitral septal annulus velocity (E/Em), (3) peak velocity of appendage outflow (ApVmax) and (4) time delay from QRS onset to appendage outflow (TDqa). Results Table summarizes the comparison of the measured parameters before and after the ablation. LA volume was significantly reduced after the ablation. The E/A ratio increased significantly but E/Em did not change significantly. ApVmax decreased significantly after the ablation. TDqa decreased significantly, which indicated that the onset of appendage outflow was advanced after AF ablation. Conclusion LAL ablation did not aggravate mitral flow pattern and advanced the onset of appendage outflow time. It is likely that LAL does not compromise the benefit of AF ablation in terms of LA systolic function.