Well, if it helps at all, Dh's father had a heart attack and quadruple bipass less than 2 months ago. We're going in June with him. His doctor said "no problem". He can't ride anything that he has to strapped into across his chest...that's it. We plan on taking it easy, and resting a lot. Most rides, will be fine because they're slow. For example, in MK Peter Pan, Small World, Philharmagic, Haunted Mansion, Pirates of the Caribbean, Hall of Presidents, the riverboat, Jungle Cruise, shows, etc. will all be fine because they are all calm sitting and slow rides. Avoid the mountains. At MGM, Little Mermaid, B&B, Great Movie Ride, all the shows....avoid ToT, RnRC, possibly Backlot Tour, but it would probably be okay for some of the examples listed. At AK, I would avoid most of the rides actually. Those would be on an individual basis depending on the situation. The safari should be okay, but very bumpy. At Epcot, Living with the Land, El Rio del Tiempo, Ellen's Energy, Figment would be fine. Avoid Mission Space, Test Track in most cases, and possibly Maelstrom depending on how extreme the situation. Overall, most rides are very tame and enjoyable to all. I wouldn't worry about it! Don't let them get too tired or hot, just like everyone else!!