Background: In the PARADIGM-HF trial, Heart failure with reduced ejection fraction (HFrEF) patients on (sacubitril/valsartan) had a substantially lower rate of hospitalization for HF and mortality compared to Enalapril. Only very few data exist regarding the impact of sacubitril/valsartan on arrhythmia in those patients. Objective: To assess the effect of Sacubitril/Valsartan combination on prevalence of arrhythmias in HFrEF patients and compare it with patients on Angiotensin converting enzyme inhibitor (ACEI) or Angiotensin receptors blockers (ARBs). Patients and Methods: Sixty patients with heart failure with reduced ejection fraction were classified into: Group A on Sacubitril\Valsartan combination therapy, and group B on ACEI or ARBs for at least 3 months with follow up as regard the burden of arrhythmia by 48 hours holter monitoring at 3 and 6 months. Results: There was no significant difference in both groups as regard demographic and medical data Group A was characterized by significant decrease in ventricular ectopics and significant improvement in ejection fraction (EF), Left ventricular internal dimension (lVIDd) and right ventricular systolic pressure (RVSP) (p=0.00) in comparison to group B. Conclusion: Sacubitril/Valsartan combination therapy was superior to ACEIs or ARBs in reducing ventricular ectiopic as a mechanism for preventing of sudden cardic death (SCD).