What is happening to my mother?

Last Monday (March 8) my mom woke up around 11pm unable to breathe well. I called 911 and when the ambulance got here she was only at 70% oxygen. (She has hyperthyroidism and now she has a goiter). She was released from the hospital on Friday and the next day her blood pressure was really high (182/107) and had chest discomfort (pressure, not pain) and was short of breath (but not as bad as Monday) so we took her to another hospital (the other one has a bad reputation). The hospital staff took a chest x-ray, and had her do a stress test and it came back abnormal. She is having a cardiac catherization today. Is it possible that she had a heart attack and didn’t know? Perhaps it happened last Monday before she woke up and couldn’t breathe? Maybe a thyroid storm? No one is giving us a straight answer, so hopefully someone here can help.