Ha, paranoia, a nasty little thing, i used to smoke marijuana for about 10 years straight, paranoia was the thing that made me stop. Any little thought that is negative can convince you of anything no matter how ridiculous. This is one of the things all the ecig haters dont take into consideration.. The fact remains, what you are doing is infinitely better than continuing to smoke real cigs, it's not just the nicotine that increases the heart rate, in fact one of the worst effects of real cigs is the carbon monoxide, it bonds to your red blood cells better than oxygen. Basically, this means when you smoke real cigs, less oxygen is able to circulate in your blood stream, this in turn means your heart has to pump harder as your muscles still require the same level of oxygen and therefore require more, less oxygenated blood. Not to mention the thousands of cancer causing chemicals that add to this total mess that you inhale with normal cigs. Keep going, you have started along the right path, it may not be the same path that others have chosen, but it is as equally a correct path. Ignore the haters, try and ignore the cigs and ask as many questions as you need. I've tried to quit more times than i care to remember, ecigs have helped me quit for the longest time yet, nearly 2 months so far.