This from Mark Sheldon Wednesday at mlb.com:
Votto was still feeling the effects of the flu [Wednesday] and went through a battery of tests after his dizzy episode during the fourth inning of Tuesday's game. He expects to be back on Friday at San Diego. The issues started in the third inning when Votto charged on a bunt play with Dan Haren up.
"I felt a little off then," Votto said. "Then during my at-bat, I felt my heart really racing and I felt really odd. After I flew out to finish the inning, I was on the field and I couldn't center myself."
Votto said there was "no question" that what happened had to do with the flu that he had last week and caused him to miss four starts.
"I wasn't dehydrated," Votto said. "I've been doing my best to eat really well and put a lot of fluids in because I realize how hot and dry it is here. It took way too long to recover after it happened.
That's where my concern was. I didn't feel regular the way I do now until maybe an hour or hour and a half after it happened. The game was over and I still felt odd. More than anything, it was frustrating. I've gotten dizzy before from heat when I was kid if I exercised and recovered quickly - 15-20 minutes at most.
"The last thing I want to do is go out there and be taken out of the game. I found it really embarrassing. Not that I did anything to justify being embarrassed. I just don't like being taken out in the middle of the game, ever, out of respect to my teammates."