<prompt> Essential criteria for TOF includes all except ?Valvular stenosisInfundibular stenosisOverriding of aoaRVH  <response>: Ans. is a i.e., Valvular stenosis o Right ventricular outflow obstruction is one of the characteristic of tetrology of fallot. This right ventricular outflow obstruction is mainly caused due to infundibular stenosis. Pulmonary valve stenosis alone rarely contributes to the right ventricular outflow obstruction in tetralogy of fallot. Hurst cardiology says The pulmonary valve is often malformed, usually being either biscuspid or unicuspid. The valve may contribute to pulmonary stenosis, but, only uncommonly, it is the only site of significant obstruction to the pulmonaryflow. Causes of right ventricular outflow tract obstruction. i Infundibular stenosis 45 ii Obstruction at the pulmonary level 10. iii Combination of infundibular and valvular obstruction 30. ivPulmonary atresia 15. 