This study looks at people with heart failure who are admitted to the hospital. The goal of the study is to understand whether taking a heart failure medicine called angiotensin receptor-neprilysin inhibitor (ARNI) before hospital admission affects short-term health outcomes.

The study will compare two groups of participants: those who were already taking ARNI before coming to the hospital and those who were not. Information will be collected from medical records during the hospital stay, including heart-related events, kidney-related events, and how long participants stay in the hospital.

Some participants will also be followed for a short period after discharge. This study may help improve understanding of outcomes associated with ARNI use in people with heart failure in routine clinical care.

Inclusion Criteria:

• >= 18 years, male or female EF <40%

Exclusion Criteria:

• EF>40% Pregnancy or breastfeeding

The study population consists of adult patients with heart failure and reduced ejection fraction who are admitted to the cardiology wards at Mansoura University Hospital (MUH) during the study period. Participants include those who were already receiving ARNI therapy prior to hospital admission and those who were not, representing typical patients seen in clinical practice.