I try not to use the rescue inhaler unless I'm having a singularly bad time of it because I get similar symptoms. It too is albuterol and it too makes my heart race and makes me shaky. On the other hand, when I do take it it's usually because I'm noticeably breathing "thickly" (it feels like my lungs shrunk about 25%) and my heart is doing some sort of weird skip beat tango. I'll take shaky and racy over irregular heart beat and trouble breathing (those freak me out more, actually). *shrug*. I asked the doc about that and he told me that albuterol is a stimulant which opens the air ways and increases your heart rate to circulate the limited air faster. And also probably a steroid. I can't remember which inhaler is what.