Exercise intolerance in adults with congenital heart disease

Exercise intolerance is a common feature of congenital and acquired heart disease. It affects approximately one third of adults with congenital heart disease (CHD) and is present in all congenital groups, including those with simple lesions [1]. Its clinical manifestations are exertional dyspnea or exertional fatigue, and it is one of the most frequent causes of reduced quality of life in adult CHD (ACHD) [2-4]. CHD shares important features with heart failure in patients with acquired heart disease, both in the clinical presentation and systemic manifestations. CHD is, in fact, a cause of the so-called heart failure syndrome. Traditionally, heart failure was identified with left ventricular systolic dysfunction of idiopathic or ischemic origin. Recent American College of Cardiology/American Heart Association (ACC/AHA) and European Society of Cardiology guidelines define heart failure mainly on the basis of symptoms of exercise intolerance and recognize it can be caused by various cardiac disorders beyond left ventricular systolic dysfunction [5,6]. It has become apparent that heart failure is a clinical syndrome with numerous systemic manifestations and multiple potential causes, including CHD. This article describes the ways to assess exercise capacity in CHD and the impact of exercise intolerance in the ACHD population. It also discusses the likely pathogenesis of exercise intolerance in CHID, the similarities between ACHD and acquired heart failure, and potential therapeutic options.