in book 2 of jim huimbles i am pretty sure he talks about heart issues and mms but i am not sure exactly what it says. i think someone posted about it on here not too long ago... check back a few forum pages ago.
my mom also has concerns about going off her vitamin c and doing mms so she just does the mms at night and the vit c 12 hours later in the morning. maybe you can do the same thing. just keep the mms 10-12 hours apart from the vit c. you just wont be able to do the 2 or 3x a day but atleast your getting mms in there... atleast that is what my mom has decided.
if you really want to find out more about it you might want to contact Denis Richards who is a supplier om mms website. his contact infor is on there and even his phone number. i think he has alot of useful things to say about this topic.