Aneurysm
An is an outward bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood wall. Aneurysms may be a result of a condition or an acquired disease. Aneurysms can also be a nidus for clot formation () and embolization. As an aneurysm increases in size, the risk of rupture increases, which could lead to uncontrolled bleeding. Although they may occur in any blood vessel, particularly lethal examples include aneurysms of the circle of Willis in the brain, aneurysms affecting the thoracic aorta, and aortic aneurysms. Aneurysms can arise in the heart following a heart attack, including both and septal aneurysms. There are atrial septal aneurysms, a rare heart defect.
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