Palpitations are generally a symptom of anxiety
and often become worse the more anxious a person gets. They can be very unpleasant though on their own not life threatening.
Simple deep breathing exercises can reduce this symptom. Take a very deep breath, hold it for 10-15 seconds and exhale very slowly through the mouth in a blowing fashion. Repeating this exercise every so often (though not every breath) can slow down the heart rate
and reduce the amount of adrenaline
circulating around the body. Adrenaline is a stimulating hormone, when released into the bloodstream at times of heightened anxiety can speed up the heart rate. These breathing exercises can help reverse this process.
It is however important to have your condition checked out by your Doctor as soon as you can to rule out any other possible cause. If it is due to anxiety s/he will help identify any cause (if any) and prescribe or recommend appropriate treatment. Treatments can range from medication; primarily a beta-blocker
- a non-addictive drug used to slow the heart rate down, to psychological and behavioural therapies.
As for your throat sensations, I have never heard of the 'rushing blood' experience, but often people with extreme anxiety describe the feeling of not being able to swallow easily. Again, your Doctor will advise
Hope this helps