Tachycardia comes from the Greek words tachys (rapid or accelerated) and kardia (of the heart). Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heartrate (heartrate in an inactive or sleeping individual). In humans, this rate's usually based upon age, sometimes it can be very dangerous depending on how hard the heart's working and the activity: 1-2 days: >159 beats per minute (bpm) 3-6 days: >166 bpm 1-3 weeks: >182 bpm 1-2 months: >179 bpm 3-5 month… (More on Tachycardia)