All of the following are characteristic features of Tricuspid Atresia except –
Left Axis deviation
Right ventricular hypoplasia
Pulmonary vascularity is diminished
Splitting of S2
Atresia of the tricuspid valve results in the absence of a communication between the right atrium and right ventricle therefore the right ventricle is underdeveloped the inflow portion being absent.
The only exit for systemic venous blood coming to the right atrium is by way ofAtrial Septal defect. Through this the blood goes to left atrium from where it enters left ventricle.
A ventricular septal defect provides communication between the left ventricle and the outflow portion of the right ventricle. The left ventricle therefore maintain both the systemic as well as the pulmonary circulation thus there is hypertrophy of the left ventricle which is reflected by left axis deviation in ECG.
The pulmonary blood flow is dependent on the size of the ventricular defect, the smaller the VSD, the lesser the pulmonary blood flow. 90% patients of Triscuspid Atresia have diminished pulmonary blood flow.
Auscultatory finding in case of Tricuspid Atresia -'


S 1- Normal                o SZ - Single           o Murmur grade III to grade 1111 / VI