What Is Tachycardia? What Causes Tachycardia?
Tachycardia refers to a faster than normal resting heart rate – the heart rate of a resting or sleeping individual is faster than it should be. In humans, the threshold of a normal heart rate (pulse) is generally based on the person’s age. Tachycardia can be dangerous; depending on how hard the heart has to work. In general, the adult resting heart beats between 60 and 100 times per minute (some doctors place the healthy limit at 90). When an individual has tachycardia the upper or lower chambers of the heart beat significantly faster – sometimes this happens to both chambers. When the heart beats too rapidly, it pumps less efficiently and blood flow to the rest of the body, including the heart itself is reduced. The higher-than-normal heartbeat means there is an increase in demand for oxygen by the myocardium (heart muscle) – if this persists it can lead to myocardial infarction (heart attack), caused by the dying off of oxygen-starved myocardial cells. Some patients with tachycardia
