it is a good question. The anwwers is YES, - MI + non or poorly treated elevated SBP increase the mortality. I am doing an anlysis to answer much it is. Hopefully, it is can be done in 2013.
I've just defended my thesis on cardiogenisc shok in acute myoacrdial infarction, with data from our own academical centre. If you like, I can send a copy to you