Final answer:
A junctional rhythm with a heart rate of 125 is called tachycardia, an arrhythmia that exceeds the normal adult heart rate of 100 beats per minute and may signify heart disease or other health issues.
Step-by-step explanation:
A junctional rhythm with a heart rate of 125 beats per minute is called tachycardia. This term is used to describe a heart rate that exceeds 100 beats per minute in adults. Tachycardia can occur in various situations, such as with exercise, stress, or certain medical conditions. It is an arrhythmia that can be a sign of heart disease or other health issues and requires further evaluation by a healthcare professional. A normal, rhythmic beating of the heart is called sinus rhythm, and any significant deviation from this can indicate a problem within the heart's electrical system.