AbstractThe Fontan operation was introduced in 1968 as a palliative treatment for patients with univentricular heart physiology. Natural history and outcomes are poor. By 10 years after Fontan operation, most patients will develop any complication such as tachyarrhythmias, any spectrum of Fontan‐associated liver disease, protein‐losing enteropathy, heart failure, thrombosis, and infective endocarditis among others. Echocardiography and magnetic resonance imaging (MRI) are the first‐line diagnostic tools for detecting such complications. Clinical and imaging follow‐up are a mainstay for the evaluation of this patients.