Damaged heart tissues, anemia, high blood pressure, and disease or congenital abnormality of the heart are causes of fast heart rate. A heart rate of over 100 beats per minute, also known as tachycardia, is also caused by excessive alcohol consumption, hyperthyroidism and medication side effects, according to Mayo Clinic.
There are three types of tachycardia, including atrial or supraventricular tachycardia, sinus tachycardia and ventricular tachycardia, claims the American Heart Association. Supraventricular tachycardia is caused by abnormal heart circuitry that is typically present at birth. Ventricular tachycardia originates from abnormal electrical signals in the ventricles. This type of tachycardia is usually life-threatening, says Mayo Clinic.