tachycardia /tak′ēkär″dē·ə/ [Gk, tachys, fast, kardia, heart] , a condition in which the heart contracts at a rate greater than 100 beats/min. It may occur normally in response to fever, exercise, or nervous excitement. Pathological tachycardia accompanies anoxia, such as that caused by anemia; congestive heart failure; hemorrhage; or shock. Tachycardia acts to increase the amount of oxygen delivered to the cells of the body by increasing the rate at which blood circulates through the vessels. Compare bradycardia.
