Tricuspid atresia occurs when the tricuspid heart valve is missing or abnormally developed. The defect blocks blood flow from the right atrium to the right ventricle. Ultimately blood cannot enter the lungs, where it must go to pick up oxygen.
Review Date 10/17/2017
Updated by: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.