what would cause increased heart rate then decrease it
Symptoms and Signs. Increased levels of thyroxine released from the thyroid gland stimulate the heart to beat more quickly and more strongly. Initially this may produce a fast heart rate which is called a tachycardia. This is observed by a nurse or physician but is usually not noticed by the patient. However, if the fast heart rate becomes severe then palpitations may be observed by the patient. This is an awareness of the heart beating within the chest. Occasionally it can be noticed by normal individuals and may be caused by excessive exercise or drinking too much caffeine.