Which term describes an abnormally fast heart rate?

• A. Bradycardia
• B. Arrhythmia
• C. Tachycardia
• D. Hypertension

Answer: (C)

Understanding how we describe heart rate is key: in a resting adult, normal heart rate is roughly 60–100 beats per minute. When the heart beats faster than 100 bpm, the condition is called tachycardia. This term specifically names the rapid rate, regardless of why it happens. Bradycardia describes a slower-than-normal rate (below 60). Hypertension refers to high blood pressure, not the speed of the heart. Arrhythmia means any irregularity in the heart's rhythm; a fast but regular rhythm would still be tachycardia, but tachycardia emphasizes the high rate itself. So the description of an abnormally fast heart rate is tachycardia.