Hi! I'm 20 years old and I have premature ventricular contractions, and when I got a procedure done where I was getting anesthetics (it didn't have to do with my heart) they wanted to keep me for a while after the procedure as well. So, there is clearly more of a concern for people with heart abnormalities when they have anesthetics in their system. It can probably throw something off but it's just a safety precaution. If it was REALLY risky they'd say so. They don't want to risk something that rarely goes wrong, going wrong in your home, so they want to keep you just in case something were to happen so that you can have the proper care. I've had anesthetics a few times and all times the doctors were concerned, however everything turned out fine.
I'm sorry to hear about your problem. That is something that would really distress me as well. I tend to obsess and worry a lot... but I find the best thing to do is to occupy your mind with something else. Learn to just let yourself relax, as hard as it is because its made your life so limited at this point. Watch a lighthearted movie or take a bath or read a book or paint something or visit with someone. Just do things to keep your mind off this horrible thing. Worrying will really stress your body out and make you feel worse. If you read past posts of mine--- you'll start to see that I became incresingly hypochondriacly worried that I was very sick... I couldnt eat, couldnt sleep, felt, weak tired and dizzy... well whatta you know as soon as I forced myself to stop thinking about all these symptoms and thinking I was sick... they went away. Now I'm constantly eating and sleeping well and energized and I don't feel lightheaded anymore. Your mind has alot more to do with your health than you think, so don't let your mind go out of your control as well. Letting yourself relax and realizing worrying won't change anything will make you feel so much better. I hope you are ok and wish you the best of luck for your procedures and the future of your condition. Take care!