30 patients, age range older than 18 years old suffering from Heart Failure, Functional capacity II-III and echocardiographic evidence of Left Ventricular Ejection Fraction less than 40% beginning Cardiac Rehabilitation Programme. Following recruitment of patients to the study each one will undergo serum KLOTHO Hormone level assessment along with kidney functions, N terminal -Pro B-Type Natriuretic Peptide hormone activity and Echo measurements .