Perhaps as Jeff above said, maybe it was the Lupus that did that to your heart. I don't know much of anything about that disease. Hopefully they can get it under control and then maybe your heart will heal up. Problem is, what caused it to come on in the first place. Here is what is says on the Mayoclinic:
"Causes
Lupus occurs when your immune system attacks healthy tissue in your body (autoimmune disease). It's likely that lupus results from a combination of your genetics and your environment.
It appears that people with an inherited predisposition for lupus may develop the disease when they come into contact with something in the environment that can trigger lupus. The cause of lupus in most cases, however, is unknown. Some potential triggers include:
Sunlight. Exposure to the sun may bring on lupus skin lesions or trigger an internal response in susceptible people.
Infections. Having an infection can initiate lupus or cause a relapse in some people.
Medications. Lupus can be triggered by certain types of blood pressure medications, anti-seizure medications and antibiotics. People who have drug-induced lupus usually get better when they stop taking the medication. Rarely, symptoms may persist even after the drug is stopped."
How old are you now? Are you still in the hospital I hope?
https://www.mayoclinic.org/diseases-conditions/lupus/symptoms-causes/syc-20365789
The article mentions how medications can trigger it. Did you start taking anything new to you recently that might have caused the Lupus? Since drugs can trigger it, it could be anything new you started up.