Dissipative energy loss (EL), an index of inefficient blood flow, has not been studied in patients with atrial fibrillation (AF). We therefore assessed the effect of AF and of successful catheter ablation on left ventricular (LV) EL and global longitudinal strain (GLS) to explore the effect of inefficient blood flow on LV remodeling. In 53 patients undergoing catheter ablation for AF (AF group), LV EL (in mW/m) was evaluated by vector flow mapping (VFM) during systole (ELsys), early diastole (ELed) and atrial contraction phase (ELac), and GLS was calculated by two-dimensional tissue tracking (2DTT). Of the 53 patients, 37 patients who sustained sinus rhythm and completed echocardiographic evaluation at baseline and at 3 and 6 months follow-up were examined for change in EL and GLS. The latter parameters also were assessed in 44 age- and sex-matched controls. At baseline in AF group, ELsys and ELed were significantly higher (3.97 ± 2.29 vs. 3.14 ± 1.01; and 9.22 ± 5.01 vs. 3.89 ± 1.51; both P < 0.05, respectively), and GLS was lower (− 16.66 ± 3.50 vs. − 19.95 ± 2.40, P < 0.05) than in controls. During follow-up after catheter ablation, ELsys and ELed significantly improved at 3 months, and almost normalized at 6 months (both P < 0.05); GLS also improved significantly (P < 0.05). In multivariate logistic regression analysis, ELed was the only independent predictor for maintenance of sinus rhythm at 1-year follow-up (hazard ratio, 1.254; 95% confidence interval 1.073–1.467). VFM and 2DTT revealed impaired LV EL and GLS in patients with AF. Successful catheter ablation appeared to ameliorate impairment in intraventricular flow and mechanics.