oh yeah it can be a sign of stress and anxiety...it's a viscious circle - your heart misfires or has a crossed/mixed signal then you start to worry or get stressed then the adrenaline pumps into our systems and starts more misfiring and signals then we get anxious, stressed more etc...
what really gets me is stress or if I get ticked off - bad mistake on my part... then by the time it's all finished I'm in bed for days at a time because my mixed up heart/ans/ brain system can't handle it all and makes me sick.
What's helped me is Inderal and Lamictal, although some do well on Ativan or Xanax and even Lexapro; so you have to find what works for you - meditation, relaxation or meds - or a combination of things - I used to do quite well with exercise almost daily; it can really help all around
if you haven't you should have a full cardiac workup to make sure everything is fine cardiac wise, then ask about meds that may help with arrhythmia's & anxiety/stress
Stress can definitely play a factor in how you feel and it will definitely make whatever is going on worse. Do you know how fast your heart is beating or does it feel like it is missing beats. To be safe you should go see your doctor for a check up. It is likely nothing to be concerned about but anything to do with the heart my policy is better to be safe than sorry. Good luck and let us know how it goes.