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.
Update Date 11/5/2013
Updated by: Kurt R. Schumacher, MD, Pediatric Cardiology, University of Michigan Congenital Heart Center, Ann Arbor, MI. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.