I don’t have personal ecperience with this. It seems likely that (congenital) heart conditions are under-disgnosed in rabbits -many rabbits die very suddenly without seeming go have been ill, and the owner never gets to know the cause.

An enlarged heart doesn’t happen suddenly, and it’s only been a short time since your Adi passed.l, so that’s unlikely to have caused it. Any pre-existing condition can of course flare up when sth traumatic happens, like the loss of a bonded partner. You did your utmost to stop that from happening with the care and love you gave Adi, but it happened anyway. As Wick says, it’s pointless to speculate, because things are what they are regardless.

I’m sorry she refses her meds. Have you told the vet? Maybe the heart takes up a lot of space in her chest cavity so it’s difficult for her to swallow any food?