Welcome to Healthcaremagic.
The symptoms you have are very typically seen in people with anxiety
further on EKG will rule out more than half of cardiac illnesses.Hence , I would not consider it to be related to the heart.It could be well ascertained by getting an 2D echo test of the heart which shows even the structural abnormality which an EKG dont.
Do go for natural mind relaxation techniques
they will help.
Wish you good health.