What does the term "tachycardia" indicate?

The term "tachycardia" refers specifically to an abnormally fast heart rate, typically defined as a heart rate exceeding 100 beats per minute. This condition can arise from various factors, including stress, exercise, fever, or underlying medical issues. Understanding this definition is crucial for recognizing potential cardiac concerns that may require medical intervention or monitoring.

In contrast, the other options describe different cardiac conditions. An abnormally slow heart rate, often referred to as bradycardia, is characterized by rates under 60 beats per minute. A normal heart rate falls within the range of 60 to 100 beats per minute, indicating a healthy cardiovascular function. An irregular heartbeat, or arrhythmia, involves variability or unpredictability in heart rates, which is not synonymous with the consistent definition of tachycardia. Thus, the choice indicating an abnormally fast heart rate accurately captures the essence of what tachycardia signifies.