True statement about ductus Arteriosus is –

This question deals with the changes in blood circulation that occur at birth : Closure of Ductus arteriosus The closure occurs almost immediately after birth by contraction of its muscular wall, mediated by bradykinin. i.e. Physiological closure. Anatomic closure occurs by proliferation of intima, and may take from 10-21 days (& not in 24 hrs. as given in choice 'A'). After obliteration, it forms ligamentum arteriosum. (& not the ligamentum venosum as given in choice 'ID') Ligamentum venosum, on the other hand, is formed by closure of the ductus venosus. "In neonates with congenital heart defects, till surgery is undertaken, PGE1 (Alprostadil) is used to maintain patency of ductus arteriosus". Therefore prostaglandins maintain patency of ductus arteriosus, and not induce it to close (as given in choice 'C'). Prostaglandins maintain patency of ductus arteriosus NSAIDs - help in early closure of ductus arteriosus "Shunt murmur is a continuous machinery murmur". The murmur is best heard at the 2nd left intercostal space and is also well heard below the left clavicle, where it maintains its continuous machinery character.