How is tachycardia defined?

Tachycardia is defined as a heart rate that exceeds the normal resting rate, typically set at greater than 100 beats per minute for adults. This elevated heart rate can be a physiological response to various factors such as anxiety, stress, exercise, or it might indicate an underlying medical condition, such as fever or cardiac issues. Understanding this definition is crucial for EMTs and medical professionals when assessing patients, as tachycardia can significantly impact a patient's overall health and management strategy. The other options do not accurately describe tachycardia; for instance, a heart rate lower than 60 beats per minute describes bradycardia, while varying heart rates or a steady rate of 80 beats per minute fall outside the definition of tachycardia.