RT Book, Section A1 Cedars, Ari M. A1 Kutty, Shelby A1 Doshi, Ashish A2 Fuster, Valentin A2 Narula, Jagat A2 Vaishnava, Prashant A2 Leon, Martin B. A2 Callans, David J. A2 Rumsfeld, John S. A2 Poppas, Athena SR Print(0) ID 1202451553 T1 Shunt Lesions T2 Fuster and Hurst's The Heart, 15e YR 2022 FD 2022 PB McGraw-Hill Education PP New York, NY SN 9781264257560 LK accesscardiology.mhmedical.com/content.aspx?aid=1202451553 RD 2024/10/10 AB Chapter SummaryThis chapter discusses the various types of congenital cardiac shunt lesions, their anatomy, physiologic impact, epidemiology, clinical presentation, work-up, and management. In congenital shunt lesions, a fundamentally important link exists between anatomy and physiology, such that the location of a shunt dictates its physiologic impact and likely sequelae. As a general rule, shunts upstream of the tricuspid valve (including atrial septal defects and accompanying partially anomalous pulmonary venous return) lead to volume overloading of the right atrium and right ventricle with consequences related to right-sided chamber dilatation and dysfunction. By contrast, shunts downstream of the tricuspid valve (including ventricular septal defects and patent ductus arteriosus) result in volume loading of the left atrium and left ventricle with accompanying consequences. Each lesion has unique associations with other cardiac abnormalities and genetic syndromes. Fundamentally important to all cardiac shunts is the downstream impact of pulmonary overcirculation on the pulmonary vascular bed. Changes in pulmonary vascular physiology, including the development of pulmonary arterial hypertension, play a major role in dictating prognosis and therapeutic decision-making.