I have a heart problem too, or had depending on how you look at it. I don't ride with a heart monitor though, I've considered getting one but It's not that big a deal for me. I know when I'm pushing myself, that is when I usually push a little harder. A wide saddle will be plenty comfortable if you're riding short distances at a slow pace. Once you start riding further, faster, it may/will give you saddle sores. If you plan on taking it easy at first it should do you well, but eventually you are going to need a saddle that suits your needs better.