I have the EXACT combination of the OP's and your symptoms, Dave. I hate being so dependent on my heart and having to listen to my heart all day and making it beat even faster by thinking about it. Basically it controls me, I am even afraid to work out. And I know exactly what you mean by not wanting to live at some points. And it's not like I don't want to live per se, that's not it, I don't feel depressed or particularly unhappy, but when the panic attacks do occur they are so terrifying and so suffocating and when I feel like my heart is going to stop just like that, those are the moments I don't want to live because it makes my life absolute hell. The most important thing is not to self-diagnose. For the past couple of years I have had all kinds of diseases from cancer to, now, heart disease (all of them in my head).
Have you had your heart checked out? Having someone other than yourself tell you that nothing is wrong does wonders to the peace of mind. Also, think about it, if you had those heart problems that you described at 19 and now you're in your 30-ies, what does that tell you? You made it this far, everything is OK! I had a terrible thing a year ago where my heart didn't skip a beat just once or twice, it continued in a chain for HOURS, and I told myself I was dead that night, but guaranteed that at the time it was because I smoked very excessively and a LOT more than usual in the days leading up to the episode.
Speaking of smoking, I agree that smoking somehow makes it better, even though it obviously speeds up my heart rate. It really does relieve some stress. And whenever I would completely stop smoking, that's when I also noticed I started getting bad palpitations, I don't know if it was mental stress from not smoking or the fact that the body is in shock from such instant cessation.
Hope this was at least a touch useful and I didn't ramble on, it's nice to be able to share with people having the same problems.