This is a mono-center observational ambispective study in which adult patients with congenital heart disease evaluated at our institution will be enrolled. The primary endopoint is to assess the clinical and echocardiographic predictors of adverse events during follow-up (death, arrhythmias, cardiac hospitalization). The secondary endpoints are: 1) evaluation of the incidence of the singular components of the primary endpoint; 2) evaluation of the prognostic impact of acquired lesions, including valve disease not present at birth; 3) need for surgical/percutaneous interventions during follow up. Participants will be evaluated in the context of scheduled follow-up visits in our Outpatient ACHD Clinic. No interventions/drug administration will be performed other than those required by standard clinical practice.