What is the definition of tachycardia?

Tachycardia is defined as a heart rate that exceeds 100 beats per minute (BPM) in adults. This condition can be classified into various types based on the exact heart rate and the underlying causes, but the key distinguishing factor is the threshold of 100 BPM. Therefore, the correct definition encompasses any heart rate above this baseline, making it distinct from bradycardia, which is characterized by a slower than normal heart rate.

While some might consider higher rates, such as over 160 BPM, as more severe forms of tachycardia, it is not the definition itself. Similarly, a normal resting heart rate or a slower heart rate do not fit within the definition of tachycardia. Understanding this measurement is crucial for the assessment of cardiac health and the recognition of potential metabolic or physiological issues requiring attention. Hence, the important boundary for tachycardia remains over 100 BPM, which signifies increased cardiac activity.