Which phase of the cardiac cycle produces the greatest amount of pressure?

• A. Atrial contraction
• B. Systolic
• C. Diastolic
• D. Isovolumetric contraction

Answer: (B)

During the heart’s pumping phase, pressure rises as the ventricles contract to push blood into the aorta and pulmonary artery. This action happens during systole, when the ventricles generate enough force to overcome the afterload and drive blood into the circulation. Atrial contraction occurs with only modest pressure in the atria, and during diastole the heart relaxes and pressure falls. Isovolumetric contraction is a brief part of systole where pressure in the ventricles rises with all valves closed, but the peak pressure that the arterial system experiences is reached during systole as ejection occurs. So the phase that produces the greatest pressure is systole.