The Effect of Inflammation in Heart Failure

Background: Heart failure is a serious health condition. Researchers believe inflammation plays a role. They want to see if adding an additional heart drug to a person s treatment can help treat heart failure with preserved ejection fraction (HFpEF). Objective: To learn if chronic inflammation is high in heart failure and if taking dapagliflozin along with the standard of care medicines for 6 months will reduce inflammation and improve heart function in people with HFpEF. Eligibility: People aged 18 and older who have heart failure and qualify for dapagliflozin therapy. Healthy adult volunteers are also needed. Design: * Participants will be screened with: * Medical history * Physical exam * Heart function tests * X-ray scans of the heart and blood vessels. They may receive medicines to slow their heart rate or make their heart blood vessels bigger. An intravenous (IV) catheter will be placed in their arm to inject contrast. * Blood and urine tests * Participants will have up to 3 study visits. Some screening tests will be repeated. Participants will take one tablet of the study drug daily for 6 months. -Participants will have an imaging scan of their heart and blood vessels. They will receive a contrast and stress medicine through an IV to view blood supply. Participants will have a stress test that measures exercise ability. They will wear sticky pads on their chest, a blood pressure cuff, and a mask. They will also have a 6-Minute Walk Test. Participants will complete questionnaires about their symptoms and their health. Participants may be on the study for up to 6 months. They will have a follow-up phone call 1 month after treatment ends. ...