CLASSIFICATION OF TRICUSPID ATRESIA

Tricuspid atresia is divided into three main types depending on the relationship of the great vessels, and sub classified depending on the presence or absence of an associated VSD, pulmonary stenosis or atresia.

Type	Relationship of the Great Vessels	Frequency
I       IA IB IC	Normal Great Vessels    No VSD. Pulmonary atresia    Restrictive VSD. Pulmonary atresia    Non-restrictive VSD. No pulmonary stenosis.	69%       9% 51% 9%
II      IIA IIB IIC	d-Transposition of the Great Arteries    VSD. Pulmonary atresia    VSD. Pulmonary stenosis    VSD. No pulmonary stenosis or atresia.	28%       2% 8% 18%
III	l-Transposition of the Great Arteries.	3%

REFERENCES

1. Rosenthal A, Dick M. Tricuspid atresia. In: Adams FH, Emmanouilides GC, Riemenschneider TA (eds). Moss'`Heart Disease in Infants, children and Adolescents. 4th ed, Williams and Wilkins, Baltimore 1989:903.