Johnson & Johnson, already the leader or second in markets for most of its medicines, consumer products and medical devices, showed it also wants to be a top provider of pacemakers and implantable defibrillators when it made a play a year ago for Guidant Corp. That’s no surprise, given the growing number of elderly people with faulty tickers needing such devices to stimulate the heart to beat at a healthy pace. But J&J might have to look elsewhere after rival Boston Scientific Corp., which on Monday made a higher bid for Guidant, said it could sign a merger agreement with Guidant by month’s end and close a deal in the first quarter of 2006. That statement came shortly after Indianapolis-based Guidant on Wednesday announced its board of directors decided to start talks with Boston Scientific.