Pouding of heart can be caused by abnormal heart beats. There are many causes of abnormal heart beats which can range from minor and relatively benign causes like having caffiene to more serious ones like serious heart rhythm disorders. Certain drugs can also cause the same. Since you have no history if any heart ailment in the past or any other symptoms like chest pain
or giddness with the heart pounding we are most likely dealing with a benign rhythm. I would suggest you to do the following:
Get a good baseline EKG done with a long rhythm strip. Sometimes abnormal ectopic beats can be picked up on this alone. If nothing turns out on this, we can do something called a holter monitor
that measures you heart activity continously for 24 hrs a day. We generally attach it for 1-2 days and then analyze the data. We also ask you to keep a log of the symptoms. If there are any abnormalities in the symptoms we can pick it up easily and advice further management.
Hope this helps
Dr. Om Lakhani, MD