Heart failure in adults with congenital heart disease is a major cause of morbidity and mortality. Patients with systemic right ventricle (SRV) and single ventricle (SV) are particularly at risk1, 2, 3. There are no specific recommendations for the management of heart failure in adults with congenital heart disease, whose management is based on general cardiology recommendations4,5. Sacubitril/Valsartan is validated as a treatment for heart failure in adults with acquired pathological left ventricular dysfunction (left ventricular ejection fraction (LVEF) \< 40%, New York Heart Association (NYHA) functional class II and III despite optimal heart failure therapy)7. Although this molecule is used in current practice in patients with congenital heart disease, published data are limited 6-10. The aim of our work is to describe the efficacy and tolerability of Sacubitril/Valsartan in the treatment of chronic heart failure on VDS and VU through an observational, prospective, multicenter registry. The latest heart failure treatment guidelines, updated in 202111, recommend the addition of type 2 sodium-glucose co-transport inhibitors in heart failure patients with impaired ejection fraction (class IA recommendation). Two molecules are used in current practice: dapagliflozin and empagliflozin, at a single dosage of 10 mg/day. We will also be collecting data on the efficacy and safety of iSGLT2. It should be noted that, for practical reasons, there may be a delay between the end of the 1st study period (ISACC1) of one year and the start of the 2nd study period (ISACC2). Follow-up examinations carried out during the study period will not differ from those currently recommended in current practice5.