For the past week, I've been experiencing a weird sensation with my heartbeat. It usually happens at night when I am laying on the couch watching t.v.. My heart will be beating normally then all of a sudden it will beat hard one or two times then go back to normal. I'm not sure what it is called or why it is happening. I do smoke cigarettes, and I'm sure that has something to do with it. Is this something that can be treated?