its a condition when way too much thyroid hormone is in the cells and it can be quite an ordeal to go through.
What happens with thyroid storm?
not seeing any tests and based off your post.. Most likely she will be having a thyroid uptake scan which requires iodine injection to "light up" the thyroid and scan for autoimmune Graves or abnormal thyroid sizes and blemishes.
How did they confirm hyperthyroidism? What was done to make them assume this?
Heart damage is something to be concerned w/ on hyperT. She could have been in this state for some time to have actual heart damaged cause or thyroid storm can be associated with this finding.