I have a new symptom presumably caused by Anxiety - Heart palpitations and fluttering.

In the last week or so I've become quite aware of issues relating to my heart such as missing beats, stronger heart beats and a fluttering feeling. These are almost certainly anxiety related but I have made an appointment to see my doctor just to make sure. The strange thing is I feel that most of the time I feel quite calm and then I get these odd heart symptoms and then I become more uncomfortable. 

I have come to the end of my current CBT sessions as it is felt that we have resolved many of the issues relating to the reason for me going to CBT. Unfortunately, it is like peeling an onion and as you peel back one layer you find another and I am now discovering a new mental health problem that was previously hidden by my depression. The discovery of this new issue has coincided with my new symptoms so I am quite confident that my heart problems are anxiety related - not that this helps!