Define tachycardia.

• A. Abnormally slow heart rate
• B. Abnormally irregular heart rate
• C. Abnormally fast heart rate
• D. Normal heart rate

Answer: (C)

Tachycardia means an abnormally fast heart rate. In adults at rest, a heart rate above about 100 beats per minute is typically considered tachycardic, which is faster than the normal resting range of roughly 60–100 bpm. This distinguishes it from bradycardia (abnormally slow) or a normal heart rate. Tachycardia can be a normal response to exercise, fever, anxiety, or stimulants, but it can also signal underlying conditions such as dehydration, anemia, hyperthyroidism, or cardiac problems. The core idea is that the rate is faster than normal at rest, not that it’s irregular or normal.