We have learned that America’s next TCG set will be the last Black and White set, though we do not know its name yet. It will probably be our equivalent of Japan’s EX Battle Boost.
Considering Japan is not releasing an X/Y set when the games are released in October, it makes sense that America won’t either. So it may be a while until we learn if Pokemon will use the worldwide release of X and Y as an opportunity to sync the American and Japanese TCG. Stay tuned!