Would a SYRIZA victory mean the end of the Euro?

[Mr. Morden]

What would a full blown Euro unraveling actually look like?  Since (if I'm understanding this correctly) one can't leave the Euro without withdrawing from the EU altogether, would the end of the Euro mean the end of the EU?  (Which I guess would then probably be followed some kind of rebuilding of the EU through brand new treaties, but without a common currency?)