Trouble Breathing, Numbness in arm, Extremely tired

Hey my Mom has been feeling terrible for the last few months. She was complaining about feeling light headed, while having trouble breathing, a numb arm and has been extremely tired. That was months ago, since then she's failed stress tests, and recently was given a splint as they found one of her arteries to be blocked 89%. It's been 2 weeks since they put the splint in, my mother is now at the hospital again because she's feeling the same way, but really dizzy now? She's now constantly in an endless cycle of EKG tests that aren't getting her anywhere. The worst part about this is she just turned 42? Some other notes you should take into consideration are: she's diabetic, she had high blood pressure and has been put on 4 blood pressure pills (she now has really low blood pressure.. this is bad), she had a splint put into her heart recently.
If anyone has any ideas or suggestions could they please let me know, she literally can't do anything without having problems breathing etc.
Thanks!!!