My heart is in perfect working order. It's as healthy as that of a man half my weight (Okay, technically a man of half my weight would probably be underweight if he was 6'4" tall... but not by much and his heart might be quite healthy... it's only at the extremes of starvation - say a third of my weight, that things start going really badly wrong).
My thyroid and kidneys are fine too. I don't have cancer, nor lupus nor any of the other exotic things mentioned. Basically, my veins just can't cope with all that blood so the Doctor said she'd send me to see a venologist. It's a while since I saw her though and I've heard nothing. Perhaps she likes to procrastinate too.
Of course, it could be that I have the edema just because I'm really fat but I'm not considering that yet.
I was fat as a child but then had dysentry at age 4 and never put on the weight again until I was 26. Hmm... wonder if perhaps I ought to take a trip to Laos?