We had a local lady, who I believe is in her 50's and an avid and very active cold water diver, who had an episode of IPE. I don't know how many lifetime dives she has, but it's a lot. She, if I remember correctly, is hypertensive, and had missed a couple of doses of her meds.
IPE is not a volume overload condition, as congestive heart failure in some patients can be. It's a volume redistribution problem, where some phenomenon centralizes intravascular volume to the point where the heart can't cope with it. There may also be a membrane leak component to the problem, causing fluid to exude into the airspaces where they normally would not. I have been very interested in this problem since I first read of it, because I wonder how many "unexplained" diving deaths might well have been IPE cases. What I can say is that it's poorly understood, not predictable, and you can't even say very much of use to someone who has suffered an episode, as to whether they should or should not do any further diving.
The only thing I can say is that, if you are diving and have chest pressure or unusual shortness of breath, get out of there, and do it as expeditiously as is safe.