Hormone KLOTHO Level in Heart Failure Patients That Participate in Rehabilitation Programme

30 patients suffering from Heart Failure with Ejection Fraction less than 40% start Cardiac Rehabilitation Programme, serum KLOTHO Hormone level and other labs and Echo measurements will be taken on the first visit. After completion of 3-month Rehabilitation Programme the second set of labs and Echo measurements will be taken. Than participants will be divided for 2 groups: the patients who wish to continue Rehabilitation programme for additional 3-month period and the second group that prefer to stop Rehabilitation programme after completion of the first 3 month period. For both groups additional set of labs will be taken this time and at the end of the study. The Aim of the study: to investigate association between serum KLOTHO level, physical activity and possible correlation with laboratory and echocardiographic parameters in cohort of Heart Failure patients.