The success rates of AEDS and CPR in and out of hospitals/minutes from higher medical care (paramedic and above with medicines) and out in the wilderness/on boats is pretty drastic from my experience.
We discussed putting AEDS on USCG helos at great length back around 1999 when they first came out. Because of metal and lots of salt water involved....they were not adopted at the time. Too much risk for low outcome of success.
I thint they are carrived now..but I believe the guiding principle still stands...unless a pretty high level of care is rapidly available, or the AED does a simple correction in a short amount of time, or CPR is only needed for a few minutes...survival rates are still pretty low.
So absolutely general health is a factor in survival and recovery and how the body handles recovery.
Again AEDS and CPR are great tools....but not miracles all the time...and seemingly in the boating world less than preferred.
Survival of certain medical events without hospitalization fairly quickly isn't going to be good, as he says. Heart attack, stroke, being the two that come quickest to mind. That's also when we would want an ER type doctor online to advise us of the next steps to be taken. As to AEDS and CPR they improve survival rates but they're still not to a good level by themselves.
We do keep a large medicine kit as well to follow up on treatment. Well equipped to this point but never tested at sea and hope not to be.