Background: It was proved that sacubitril-valsartan has a major role in ventricular remodeling resulting in improving ejection fraction and ventricular size. Although evaluating the diastolic function in those presenting with Heart failure and reduced ejection fraction [HFrEF] was neglected, the majority of patients with HFrEF also have diastolic dysfunction.
The Aim of the work: In this study, we will focus on studying and explaining the impact of sacubitril–valsartan on diastolic dysfunction and RVD and explaining if the clinical improvement is attributed to improvement in diastolic function and right-side function.  
Patients and Methods: Our prospective study enrolled 60 HFrEF patients. All of the included patients were submitted for, ECG, and Standard 2D Doppler transthoracic echocardiography. The following parameters were collected; TAPSE [Tricuspid Annular Plane Systolic Excursion], FAC [fractional area change] 3Systolic pulmonary artery pressure [SPAP], Myocardial performance index [M P I].
Results: According to the percentage of improvement among the studied cases, the majority [80%] of class II cases improved and 20% had no change. Similarly, 82.1% of class III patients saw improvement in NYHA classification. Whereas all cases in class IV were improved [100%]. According to the change of systolic and diastolic blood pressure, the mean Systolic Blood Pressure [mmHg] of subjects before therapy with sacubitril–valsartan was 125.88 ±13.7 and it was 108.8± 11.3 of subjects following therapy with sacubitril –valsartan, and this was statistically substantial [P = 0.001]. The mean of Diastolic Blood Pressure [mmHg] of subjects before therapy with sacubitril –valsartan was 85.25 ± 8.9 and it was 74 ± 11.1 of subjects following therapy with sacubitril –valsartan, and this was statistically substantial [P = 0.001].
Conclusion: The measured parameters of right ventricular function such as TAPSE, MPI, and Fractional area change were all improved significantly indicating a positive effect for sacubitril-valsartan on the right ventricular function.