Electrocardiogram test is done to check the heart electrical activity, and finding the cause of unexplained chest pain, which could be caused by heart attack. This test is performed for further purposes as well like checking the health of heart when other diseases such as high blood pressure, high cholesterol, diabetes, cigarette smoking and family history of early heart diseases.
In addition, it is also used to find the symptoms of heart disease (i.e. shortness of breath, dizziness, fainting, heart beats that are rapid, etc.), to find out if walls of the heart chambers are too thick and how well medicines are working and to check if they are causing any side effects to heart.