Introduction Cardiac Rehabilitation (CR) can reduce mortality and prevent Cardiovascular Diseases (CVD) recurrence, but published data do not indicate an improvement in systolic function. However, there still has not been much research into the relationship between diastolic function and functional capacity during CR. The primary goal of our study is to objectively assess the evolution of clinical data and echocardiographic measurements (including diastolic function) before and after 20 sessions of CR. Method We carried out a prospective, cross-sectional study in the Bastia CR department from December 2018 to July 2019. All patients with an indication for CR and a left ventricle ejection fraction (LVEF) superior to 50% were invited to participate in the study. The assessment on inclusion and after CR included clinic measurements, the INTERHEART score and the maximum effort load (Wattmax). Using echocardiography, we measured the LVEF, the Tei index, and the tricuspid annular plane systolic excursion (TAPSE), septal and lateral E/e’ ratio and the isovolumetric relaxation time (IVRT). Results 93 patients were included. After exclusion, there are 54 patients left for study. CR had no impact on the LVEF (P = 0.06). CR allowed a significant decrease in weight (−1 kg with P = 0.004), abdominal perimeter (−1.3 cm with P Fig. 1 ). Conclusion Thus, the benefit shown by the CR program is evidenced from both an echographic, an ergometric and a clinical point of view. These data strongly support physicians in the prescription of CR and patients in their participation in CR programmes, within the scope of CVD prevention.