What is the maximum heart rate considered a criterion for tachycardia?

Tachycardia is generally defined as a heart rate that exceeds the normal resting rate. While normal heart rates can vary depending on age, fitness levels, and other factors, a commonly accepted threshold for cardiac tachycardia in adults is a heart rate greater than 100 beats per minute. This criterion is significant in clinical practice because it helps healthcare providers identify potentially serious conditions that may be causing the elevated heart rate, such as arrhythmias, fever, hypovolemia, or underlying cardiovascular issues.

In contrast, the other options fall below the established threshold for tachycardia. A heart rate of 60 beats per minute is typically considered normal for resting adults, while rates of 80 and 90 beats per minute also fall within the broad range of normal resting heart rates. Understanding these benchmarks is crucial for evaluating patient health and managing potential tachydysrhythmias in various clinical scenarios.