Canadian here, and of Nordic heritage. So I know the struggle of cultural coldness of which you speak. Unless your coworkers are just heartless, the most like

Canadian here, and of Nordic heritage. So I know the struggle of cultural coldness of which you speak. Unless your coworkers are just heartless, the most likely thing going on here is a concern about not wanting to make it appear a big deal. Perhaps the person who had the heart attack, does not want to have everyone know about it. Some people wish to keep it quiet; they feel embarrassed. (My mother tried to dissuade me from informing even her closest friends!) And so dramatically highlighting their recent heart attack could be terribly distressing and awkward. But don't get carried away. This is more of a thing for in conversation. Should they recover and return to the office, I would not bring it up beyond a simple "so happy to see you here and looking well". I wouldn't try to discuss it with them unless they bring it up first. If the simple fact of the heart attack is in the open, then it is hard to imagine how someone could be insulted or distressed by a card, or flowers or similar note of well-wishes.