Thank you for your question.

This answer is a general description of the problem you are having. Please click on this link (DoctorOnCall) to talk to a doctor.

The heart beats rapidly or is called tachycardia, due to anxiety in the normal electric impulse that controls your heart pumping rate. Many things can cause or contribute to problems in the electrical system in the heart. This includes:
-Heart failure of heart tissue due to heart disease
-Abnormal electrical pathways in the heart at birth (congenital heart condition, including long QT syndrome)
-Congenital heart disease or disorder
-Anemia
-Exercise
-Sudden pressure, like fear
-High blood pressure or low blood pressure
-Smoking
-Fever

So I suggest you, to know the exact cause of the problem you are facing, more information about your health background, checks and tests may need to be carried out. You are advised to refer this matter further. You can click on this link (DoctorOnCall) to talk to us online.