Systolic describes which of the following?

• A. Rhythmic contraction of the heart
• B. Diastolic relaxation
• C. Rate of respiration
• D. Heart rate variability

Answer: (A)

Systole refers to the phase when the heart muscles contract, pushing blood out of the chambers to the lungs and the rest of the body. This is the pumping action that occurs during each heartbeat. Diastolic relaxation is the filling phase when the heart is relaxed, respiration rate is about breathing, and heart rate variability describes changes in the time between beats rather than the contraction itself. So the term describes the rhythmic contraction that drives blood flow.