CAMEO-FONTAN -Dapagliflozin in the Failing Fontan Circulation

This trial is testing whether dapagliflozin — a drug originally developed for diabetes and heart failure — can help adults who have a Fontan circulation. The Fontan procedure is a heart surgery done in childhood for people born with a single functioning heart ventricle; over time, these patients can develop heart failure-like symptoms. **You may be eligible if...** - You are 18 or older - You have had the Fontan procedure - You experience shortness of breath with activity (NYHA class II–III) - During a cardiac catheterization procedure, your pulmonary pressure during exercise is elevated (≥20 mmHg) **You may NOT be eligible if...** - You have type 1 diabetes - You are taking insulin or certain other diabetes/heart medications - You have severely reduced kidney function - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.