This excerpt taken from the BSX DEF 14A filed Mar 27, 2007.
Required Vote and Board of Directors Recommendation
To be approved, Proposal 4 must receive For votes from the holders of a majority of the shares of our common stock present or represented at this meeting and entitled to vote. If you abstain from voting, it will have the same effect as an Against vote. Broker non-votes will have no effect on the outcome.