This disorder is characterized by downward displacement of the tricuspid valve into the right ventricle caused by anomalous attachment of the tricuspid valve leaflets. If the tricuspid valve is severely deformed, heart failure occurs and death may result in utero or soon after birth. With mild deformity individuals may remain symptom-free into adulthood or beyond middle age. Associated malforma¬tions include a patent foramen ovale, an atrial septal defect, and pulmonary stenosis or atresia. An ostium primum atrial septal defect alone or combined with other defects indicates a bad prognosis. This abnormality may be associated with congenital corrected transposition of the great vessels. Adult patients present with shortness of breath and fatigue, palpitations, associated Wolff-Parkinson-White syndrome, cyanosis from a right-to-left shunt, and occasionally paradoxical embolus causing a cerebrovascular accident. Diagnosis is usually made from echocardio-graphic examination.