Twitter reports indicated it was Sen. Ted Kennedy. It has now been confirmed by CNN and now MSNBC as I write this.
Update: MSNBC reports the Sen. Kennedy had "convulsions" and had to be rushed out on a stretcher by medical staff.
Later reports have confirmed that Senator Kennedy is well and should be released from the hospital on Wednesday. His illness was related to exhaustion from the day and his chemotherapy for his brain cancer.
Senator Byrd was not ill as first reported.
We wish Senator Kennedy all the best.