The aim of this study is to evaluate the bio-clinical effects of sacubitril/valsartan combination in treatment of patients with Congestive heart failure. Moreover, the investigators aim to evaluate side effects of this combination.

- The following parameters were determined at baseline and at end of the study at 6 months of the beginning.

1. New York Heart Association (NYHA) Class.
2. Frequency of hospitalization by acute exacerbation of CHF
3. NT-ProBNP
4. Left ventricular systolic function by Echocardiography

Moreover, the side effects of the drugs used during study was assessed by

1. Renal function (Serum creatinine) was performed every month till the end of the study.
2. Serum electrolytes (Potassium and Sodium) was performed every month till the end of the study.

Inclusion Criteria:

1. Age 40 - 60 years
2. Patients with chronic congestive heart failure class ( II-IV) symptoms according to New York Heart Association (NYHA) classification
3. Left Ventricular Ejection Fraction of 40% or less.
4. NT-proBNP level of at least ≥400 pg per milliliter
5. ACE-inhibitor or ARB therapy with stable dose for prior 4 weeks, equivalent to enalapril ≥ 10 mg/day.

Exclusion Criteria:

1. Patients with symptomatic hypotension.
2. Pregnant and nursing women
3. Systolic blood pressure < 100 mmHg at screening or < 95 mmHg at randomization
4. Patients with glomerular filtration rate <30 mL/min/1.73 m2
5. Patients with history of angioedema
6. Patients with unacceptable side effects with ACE-inhibitors or ARBs.