Up to 20% of all postoperative patients with repaired congenital heart disease later develop symptoms of heart failure, but slow disease progression makes patients difficult to study. The incidence is higher in the presence of lesions with a solitary or systemic right ventricle (RV). Several mechanisms cause the development of heart failure in this population, and the treatment options are not always aligned to conventional therapy for heart failure in a biventricular heart with cardiomyopathy. The pathogenesis and options for management of this complex problem in specific high-risk lesions are explored. Heart failure is commonly encountered in preoperative congenital heart disease and usually effectively dealt with by cardiac surgical or catheter-based interventions. Some lesions (single-ventricle physiology, tetralogy of Fallot, and systemic RV amongst others) are never completely repaired, and others may have persistent abnormal hemodynamic loading abnormalities; patients with these remain at risk of postoperative heart failure. Treatment is multifaceted and relies on focused surgical reintervention, timely medical therapy, and, occasionally, innovative measures, such as resynchronization therapy. The authors propose a construct whereby a primary underlying cause or substrate combined with additional remodeling stimuli results in the release of second messengers acting on classical heart failure signaling pathways. Together, these factors result in progressive heart failure in certain high-risk patients with congenital heart disease. Understanding this sequence leads to a logical application of treatments at the various stages of disease.