The year I turned 37, my heart stopped. Not figuratively, I mean it actually stopped beating.

We were in the early days of launching Startups.com, and I was at lunch with our team. I couldn't quite put my finger on it, but something just didn't feel right, so I told the team I was going to head home and lay down. As I was driving home, I called my wife and told her "I'm heading home, something feels off..."

And as I said those words, my heart stopped — while driving. My world went black.

For anyone that has had their heart stop, you can't ignore it because, well, you're sorta dead. In my case, I came to quickly, recovered the car, and drove the next few minutes home. As soon as I got home I phoned my co-workers (who were 5 minutes away) and...