A cardiac aneurysm is a localized bulge in the heart wall that typically develops 6-8 weeks after a myocardial infarction (heart attack). Rarely, it can occur independently of a heart attack. It is often confused in the general public with an aortic aneurysm, which is an aneurysm of the main artery. While an aortic aneurysm refers to a ballooning or rupture in the aorta, the body's main artery, a cardiac aneurysm is a ballooning that develops due to weakening of the heart muscle tissue in the region supplied by a vessel that was blocked after a heart attack. Aortic aneurysms are more commonly observed in the general population, whereas cardiac aneurysms are much rarer.