What is the medical term for an abnormally fast heart rate?

The medical term for an abnormally fast heart rate is tachycardia. In adults, a resting heart rate above 100 beats per minute is commonly used as the clinical threshold, though age and circumstances matter.

Tachycardia can be a normal response to exercise, fever, pain, stress, or adrenaline. It can also result from anemia, thyroid disease, dehydration, stimulant drugs, or an electrical problem in the heart. The word comes from Greek tachys, meaning “rapid,” and kardia, meaning “heart.”

Tachycardia describes a fast rate, while arrhythmia is a broader term for an abnormal heart rhythm and may be fast, slow, or irregular. Palpitations are the sensation of feeling one’s heartbeat, not a diagnosis itself. Bradycardia means an unusually slow heart rate. Doctors use an electrocardiogram to identify the type and source of tachycardia.