In which phase of the cardiac cycle is diastolic pressure measured?

• A. During atrial contraction
• B. During ventricular diastole
• C. During ventricular systole
• D. During isovolumetric relaxation

Answer: (B)

Diastolic pressure reflects the arterial pressure when the heart is relaxing and not actively ejecting blood. This occurs during ventricular diastole, the period when the ventricles relax and fill. After the previous beat, the aortic valve closes and the arterial system is sustained mainly by the elastic recoil of the vessels, so the pressure in the arteries falls to its lowest level—the diastolic pressure. It isn’t set during atrial contraction or during the heart’s pumping (ventricular systole); those times correspond to higher pressures (systolic) or to events before the ventricle fills.