I have had that feeling before and it was a little scary, but went away. I am not sure what it is, I thought personally it was a little anxiety even though I didn't have anything troubling me at the time. I think it is a good idea that you are getting it checked out, so you will know for sure, being that you have other medical problems as well. It is just best to get checked.
Atrial flutter is closely related to another arrhythmia called atrial fibrillation. The two sometimes alternate back and forth.
Atrial Flutter Symptoms
Some people have no symptoms at all with atrial flutter.
Others describe the following symptoms:
Palpitations (rapid heartbeat or a pounding sensation in the chest)
A "fluttering" or tremor-like feeling in the chest
Shortness of breath
Anxiety
People with underlying heart or lung disease who experience atrial flutter may have these and other, more significant symptoms.
Angina pectoris (chest or heart pains)
Feeling faint or light-headed
Fainting (syncope)
When to Seek Medical Care
If you experience any of the symptoms of atrial flutter