Well, I haven't got a long experience of this, since I was diagnosed with CHF in early November and have only been planning valve surgery since December -- so far most people I've told about the CHF and the surgery have been really nice and concerned, even sometimes, to my mind, overly concerned! I say overly, because as a person with a disability (not heart related) that I've lived with for years, one thing I don't really like is people fussing over me. But say "heart failure" to them and it sounds so ominous, and then they start wanting to carry my groceries for me & assuring me that they are praying for me. They look at me like I am likely to drop dead right in front of them without warning. I have to reassure them that it doesn't mean THAT! So now I have stopped mentioning "heart failure" and I just tell them I am having surgery to "fix" a leaky valve. Leaving the impression, I suppose, that after it is "fixed" all will be well and I'll be as good as new (not exactly true because the surgery won't reverse the damage already done to my heart, but I'd rather not go into explanations).
I did get the "oh, open heart is routine surgery these days" line from one idiot when I went to a big lunch last Saturday, but another guy who was there, who had CABG a year or so ago, quickly set the person straight. "It may be routine for the surgeon," he said. "It's not routine for the PATIENT." He proceeded to talk about some of his experiences and the "routine surgery" guy turned rather green and just stared at his plate for a while.