What is the relationship between tachycardia and heart rate?

Tachycardia specifically refers to an elevated heart rate, typically defined as a resting heart rate exceeding 100 beats per minute in adults. This condition may arise from a variety of factors, including stress, anxiety, medications, or underlying health issues. By understanding this definition, it's clear that tachycardia signifies a heart rate that is more rapid than normal, distinguishing it from other conditions such as bradycardia (which indicates a slower heart rate) or normal sinus rhythm, which would fall within the typical heart rate range of 60 to 100 beats per minute.

In the context provided, the other options do not align with the established medical definition of tachycardia, which is why they lack the accuracy of the correct response. The notion that tachycardia indicates a slower or normal heart rate is fundamentally misaligned with its definition, as is the assertion that it denotes an arrhythmia. While tachycardia can be a type of arrhythmia if it occurs irregularly, the term itself does not inherently imply an arrhythmic condition.