Which vital sign measures the rhythm of the heart?

The pulse is the vital sign that specifically measures the rhythm of the heart. It is detected by feeling the expansion and contraction of an artery as the heart pumps blood through the circulatory system. The pulse reflects the number of times the heart beats per minute (heart rate) and the regularity of those beats (rhythm). Healthcare professionals assess the pulse to determine not only the rate and rhythm but also the strength and quality, which can provide significant insight into a patient's cardiovascular health.

Other vital signs, such as temperature, respiration, and blood pressure, are important indicators of health as well, but they do not directly assess the heart's rhythm. Temperature indicates the body's heat level, respiration measures the rate of breathing, and blood pressure gauges the force of blood against the artery walls, all of which are crucial for overall health assessment but do not provide information about the heart's rhythmic contractions.