"Left axis deviation and left ventricular hypertrophy are usually present on electrocardiogram distinguishing tricuspid atresia from most other cyanotic heart lesions.The combination of cyanosis and left axis deviation is highly suggestive of tricuspid atresia." - Nelson irk p. 1913 Tricuspid atresiaCongenital absence of tricuspid valve is called tricuspid atresia TA has following features : -Absence of tricuspid valve Hypoplastic right ventricle with absence of inflow portion of RVSo, blood can not flow directly from right atrium to right ventricle and following associated defect are neccessary for survival : -For flow of blood from RA to LA Patent foramen ovale or ASD. For flow of blood from LV to RV --> VSD (VSD is always muscular in tricuspid atresia)Therefore blood flow in following direction.