Which condition involves an increase in heart rate, typically over 100 beats per minute?

Tachycardia is characterized by an increased heart rate, typically exceeding 100 beats per minute. This condition can arise from various physiological or pathological stimuli, such as stress, anxiety, fever, or underlying medical conditions like anemia or hyperthyroidism. Understanding tachycardia is important because it can serve as a key indicator of the body’s response to stress or disease, and recognizing it can prompt timely medical evaluation and intervention.

Bradycardia, in contrast, refers to a slower than normal heart rate, generally under 60 beats per minute, which can lead to symptoms like fatigue or dizziness. Cardiac arrest is a critical condition in which the heart stops beating effectively, leading to a loss of blood flow and requiring immediate medical attention. Hypertension, or high blood pressure, is distinct from heart rate alterations; although it can strain the heart, it does not directly relate to heart rate increases. Thus, tachycardia specifically denotes the elevated heart rate that the question seeks.