IV Antibiotics are one of the worst things you can do to yourself. I had IV Antibiotics administered a decade ago when I was hospitalized for cellulitis (long story, my own fault through self-abuse) and I believe that that is part of the reason my health eventually crashed as it did. IV Antibiotics kills off your beneficial flora in droves. Think oral antibiotics times 100.
Also, I don't understand why having a heart valve problem would require one to take large doses of antibiotics before surgery. Antibiotics are to ward off bacterial infections. Is it as some sort of preventative measure? What is the rationale?