References selected and published in this document are representative and not all-inclusive. As noted in the preamble, an independent ERC was commissioned to perform a formal systematic review of critical clinical questions related to adult congen- ital heart disease (ACHD), the results of which were considered by the writing committee for incorporation CLINICAL STATEMENTS AND GUIDELINES into this guideline. Concurrent with this process, writ- ing committee members evaluated study data relevant to the rest of the guideline. The findings of the ERC and the writing committee members were formally presented and discussed, and then recommendations were developed. The systematic review reports on Medical Therapy for Systemic Right Ventricles: A Sys- tematic Review (Part 1) for the 2018 AHA/ACC Guide- line for the Management of Adults With Congenital and Interventional Therapy Versus Medical Therapy for Secundum Atrial Septal Defect: A Systematic Review (Part 2) for the 2018 AHA/ACC Guideline for the Management of Adults With Con- genital Heart Disease S1.1-2 are published in conjunction with this guideline. 1.2. Organization of the Writing Committee The writing committee consisted of pediatric and adult congenital cardiologists, interventional cardiologists, electrophysiologists, surgeons, and an advance prac- Table 1. Applying Class of Recommendation and Level of Evidence to Clinical Strategies, Interventions, Treatments, or Diagnostic Testing in Patient Care* (Updated August 2015) CLINICAL STATEMENTS AND GUIDELINES tice nurse. The writing committee included represent- atives from the ACC, AHA, and American Association for Thoracic Surgery (AATS), American Society of Ech- ocardiography (ASE), Heart Rhythm Society (HRS), In- ternational Society for Adult Congenital Heart Disease (ISACHD), Society for Cardiovascular Angiography and Interventions (SCAI), and the Society of Thoracic Sur- geons (STS). 1.3. 