She just showed you that she is completely ignorant. I would definately call her out on that. You will feel much better. I dont believe thats something you can just sweep under the rug. She knew and told you she knew, and intentionally said what she said and hurt you. I wouldnt go in bouncing around ready to fight, I would just be very mature and simply tell her that was wrong and you dont appreciate it.
I also am a very firm believer in carma. She needs to watch what she says and who she judges. She isnt in the clear of never getting MI. She could wake up in a very deep depression tomorrow or wake up in a manic episode. What would she have to say about it then? Or if she had a child born with a birth defect or MI????