Aortic stenosis means your aortic valve has a problem opening. The aortic valve is one of the heart's four valves. It's on the left side of the heart. It sits between the left lower chamber (left ventricle) and the large blood vessel that sends blood to the body (aorta). With aortic stenosis, the left ventricle has to work harder to push the blood through the valve. In some cases, this extra work will make the muscle of the ventricle thicken. In time, the extra work can tire the heart and cause the heart muscle to weaken.
Stenosis usually gets worse slowly, over many years. But sometimes, it can quickly get worse.