I hate to put a dampener on the idea that a "bad heart" has been passed down the family BUT --- the likeliest cause by a looooooong shot of heart disease in a young woman in those days would have been as an aftermath of rheumatic fever, probably as child.So secondary to an infection and not anything to do with genetics.
Congenital heart disease (ie the sort that some babies are born with) (depending on type) has some familial tendencies but only a weak link.
The commonest heart disease these days is due to atheroma, in older people, and the tendency to develop this can certainly be increased in some families, but it is also heavily associated with lifestyle --weight. smoking, lack of exercise etc -- and it's very unlikely that this young woman would have suffered from that.
Obviously we don't have the finer details, and never say never etc etc, but don't assume that "heart disease" in the 1800s was the same sort of thing as nowadays, nor that it's necessarily hereditary.