Ok, thanks, I was wondering how she was a victim of the War, but that was all if said on MB.However it does say that the second Eugenics Wars book revealed that Claire Raymond, "the lady", actually died because of the EU, not an embolism like they thought in the episode.
IIRC, the novel - which has many, many cameos from 20th century ST characters - features her being exposed to gas released by Eugenics terrorists, causing an embolism.