·         Hyoiokastic Right Heart- Most authors do not regard a hypoplastic RV as a specific entity. However, this may be considered as a part of pulmonary atresia with an intact ventricular septum or an atretic tricuspid valve in association with a VSD. When the ventricular septum is intact the RV hypoplasia is severe. With an atretic tricuspid valve, the degree of RV hypoplasia depends upon the size of the VSD. These lesions may be progressive in utero.

·         Pulmonary/ Tricuspid Atresia/Stenosis- There may be compensatory enlargement of the LV in tricuspid atresia, and the hypoplastic form of pulmonary atresia with an intact ventricular septum or atrioventricular canal (with a larger inflow to the LV and double inlet LV).

·         Normal RV functional Overload LV-This may be seen occasionally in LV dysfunction in conditions like myocarditis, endocardial fibroelastosis or the dilated form of critical aortic stenosis.

·         Ebsteins Anomaly- In Ebstein’s anomaly of the tricuspid valve, the RV may appear small as compared to the normal LV although the atrialized part of RV may be dilated.