What happens to the size of an aneurysm during systole?

During systole, the heart muscle contracts to pump blood out of the chambers, particularly from the ventricles into the aorta and pulmonary arteries. The increase in intravascular pressure during this contraction leads to the expansion of blood vessels and any existing aneurysms. Since an aneurysm is characterized by a localized dilatation of a blood vessel, the heightened pressure exerted during systole causes the size of the aneurysm to increase. This expansion occurs because the walls of the aneurysm are weakened and unable to withstand the higher pressure that is generated during this phase of the cardiac cycle. Therefore, recognizing that aneurysms respond to pressure fluctuations in the circulatory system is key to understanding why their size would increase during systole.