1. Aortic regurgitation occurs when blood leaks backwards from the aorta into the left ventricle during diastole due to failure of the aortic valve leaflets to coapt properly.
2. It can be acute, caused by things like infective endocarditis or aortic dissection, or chronic, caused by conditions like bicuspid aortic valve or hypertension.
3. Chronic AR is often well-tolerated for years as the left ventricle dilates and hypertrophies to accommodate the increased volume, but acute AR can rapidly lead to heart failure and shock if not emergently treated.