What condition is characterized by a heart rate over 100 beats per minute?

Tachycardia is defined as a heart rate that exceeds 100 beats per minute. This condition can occur in response to various physiological demands, such as exercise or stress, or may be indicative of underlying health issues, such as fever, anemia, or cardiac dysfunction. The mechanism of tachycardia typically involves increased conduction velocity or automaticity within the cardiac tissue, leading to a rapid heartbeat.

Bradycardia, on the other hand, refers to a slow heart rate, typically under 60 beats per minute, and is not related to elevated heart rates. Asystole indicates the absence of electrical activity in the heart and is a critical condition with no heartbeat, while fibrillation describes chaotic, irregular heart rhythms that can be either atrial or ventricular, which generally do not maintain an effective cardiac output. Understanding these terms and their definitions is crucial for recognizing and responding to different cardiac conditions effectively.