Thanks for your question on Health Care Magic.
I can understand your concern.
In my opinion, we should first rule out heart diseases for your symptoms before considering
anxiety attack.
You are having significant past history of atrial
fibrillation and heart surgery, so we should first rule out
arrhythmia as a cause for your palpitations.
So get done ecg, 2d echo and Holter monitoring (24 hour continuous monitoring of ecg).
If all these are normal then we can say that your symptoms are due to anxiety attack.
In that case, you need to
consult psychiatrist and get done
counselling sessions. Try to identify stressor in your life and start working on its solution.
You may need anxiolytic drugs too. Don't worry, you will be alright. First rule out heart diseases.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.