Benefits on morbi-mortality and quality of life of cardiac rehabilitation (CR) and valsartan/sacubitril (VS) association are well known in patients (P) with heart failure (HF) and impaired systolic function (ISF), but few studies reported their respective benefits on left ventricle ejection fraction (LVEF) and cardiorespiratory exercise testing (VO2 ST) parameters. The aim of the study was to evaluate the middle term respective benefits of CR and VS in P with HF and ISF under optimal therapy (OT) (betablocker+conversion enzyme inhibitor or Angiotensin 2receptor antagonist+Aldosterone antagonist+diuretics+electric resynchronization/ER if necessary) by using echocardiographic (Echo) LVEF, Relative (R)(ml/kg/mn) and Absolute (A) (l/mn) Peak VO2 (PVO2), first ventilatory threshold (VT1). Thirty two P with HF/ISF (mean LVEF at screening T0 31.7%±8)(male 90%, 64±12years, 18ischemic/I and 14dilated/D cardiopathy/C, BMI 25±7) were included in this study for CR; VS was associated when OT was obtained (initial dosage 24/26mg or 49/51 if tolerate) at T1; VO2 ST was performed at T1, the end of CR (T2) (28±9sessions, 72±40days) and six months later (T3) T2; Echo LVF was performed at T0, T1, T2, T3. Eighteen P (17male, 63years, 10IC, 3 with initial ER) were evaluated at T3 (10 P at 97/103 SV dosage, 3 P at 49/51 SV dosage, 5 P at 24/26 SV dosage); 14 P are on course; physical activity of P since T2 was low. LVEF was respetively 33% at T1 (T1/T0 NS), 40% at T2 (T2/T1 P<0.001), 47% at T3 (T3/T2 P<0.01); R/A PVO2 were respectively 15,7/1.2 at T1, 17.4/1,3 at T2 (T2/T1 NS), 20,1/1,5 at T3 (T3/T2 P<0.001); VT1 was respectively 9.4 at T1, 10.5 at T2 (T2/T1 NS), 13,7 at T3 (T3/T2 P<0.0001). We concluded that CR associated to VS and OT significantly improved at end stage LVEF; VS association despite CR seems to be able to improve LVEF and VO2 ST parameters at middle term; these results seems to be sustained at long term (one year).