What is a key characteristic of tachycardia?

Tachycardia is defined by a heart rate that exceeds 100 beats per minute (bpm) in adults. This elevated heart rate can be a physiological response to various factors such as exercise, stress, fever, or it can indicate underlying health issues. The key characteristic of tachycardia lies in the fact that this high heart rate can significantly affect the heart's efficiency in pumping blood, potentially leading to reduced cardiac output or other complications if it persists.

Recognizing the threshold of 100 bpm is essential for identifying tachycardia in clinical settings. This benchmark helps healthcare professionals assess a patient's cardiovascular status and determine appropriate interventions. While tachycardia can be related to blood pressure changes, it is not always associated with high blood pressure, nor is it defined as a lack of heart rhythm; these factors do not characterize tachycardia itself. Therefore, the correct definition emphasizes the crucial heart rate criterion that establishes when tachycardia is present.