Which cardiac event corresponds to the systolic reading on a blood pressure measurement?

• A. Atrial contraction.
• B. Ventricular filling.
• C. Ventricular relaxation.
• D. Ventricular contraction.

Answer: (D)

Systolic pressure reflects the moment the heart is actively pumping blood. During this phase, the ventricles contract and eject blood into the aorta and pulmonary artery, which raises arterial pressure to its peak. That peak is what the systolic reading captures. Atrial contraction happens earlier in the cycle and mainly helps finish filling the ventricles; ventricular filling and ventricular relaxation occur during diastole when the heart is relaxed and filling, not during the pressure peak. So the best answer is ventricular contraction because systole is the period of ventricular contraction that generates the highest arterial pressure.