"We'd like you to have a cardiac catheterization." When the doctor said those words to me recently, it really didn't register at first. Sure, I had undergone a stress test for some shortness of breath and other symptoms - but I chalked that up to being an out-of-shape fat guy. The idea something might actually be wrong, or that someone might suggest sticking a tube up into my heart, just somehow never seemed a serious possibility. After all, I'm only 55, and only 35 in my own mind. That stuff only happens to old folks. But the doctor was serious, and soon, so was I. Before I knew it, there …