Refile Visa after traveling outside USA cos of change in I-94 Number?

Hey, I got my H1b approved in month of April 2012, and after that i went to India in May 2012 and came back in August 2012, i got my H1b Approval notice also, which says i can start my job from October. But somewhere i heard that i need to refile my visa as my 1-94 has been changed coz of my travel. Is it true?? or i can straight away start my job without refiling?? Thanks so Much!