Background - Cardiac resynchronization therapy (CRT) improves left ventricular (LV) function and induces LV remodeling, and it is an established therapy for advanced heart failure with prolonged QRS duration. One third of patients will not benefit from this invasive therapy. Objective - The purpose of this study was to evaluate whether left atrial (LA) strain imaging (ε) parameters could help in predicting the response in terms of LV reverse remodeling after CRT. Methods - A total of 79 patients who underwent CRT were evaluated with echography before implantation. LA function and LV function were assessed with M-mode, 2-dimensional echocardiography, Doppler, tissue Doppler velocity, and ε. LV reverse remodeling was defined as a >15% reduction in LV end-systolic volume. Results - At 6 months, 54 patients (68%) were responders to CRT. In multivariable logistic regression, LA systolic peak of strain rate (SRA) (odds ratio [OR} 10.5, 95% confidence interval [CI] 1.76-62.1, P = .01), left bundle branch block (OR 6.8, 95% CI 1.06-43.9, P = .04), ischemic cardiomyopathy (OR 3.93, 95% CI 1.07-14.4, P = .04), and LV preejection index (OR 1.03, 95% CI 1.01-1.05, P = .01) were associated with CRT response. With an SRA cutoff of -0.75%, the negative predictive value for predicting CRT response was 0.62. Conclusion - This study demonstrated the possible relevance of assessing LA function before CRT. SRA appeared to be a good predictor of CRT response. Integrating this LA function analysis into the multivariable assessment of patient candidates for CRT should be considered.