A normal aortic valve, when open, allows the free flow of blood from the left ventricle to the aorta. When the valve narrows, as it does with stenosis, blood flow is impeded. Because it is more difficult for blood to flow through the valve, there is increased strain on the heart. This can cause the left ventricle to enlarge and malfunction, resulting in reduced blood supply to the heart muscle and body, as well as fluid build up in the lungs. Calcium deposits may form on the valve with aging, causing the valve to become stiff and narrow.
Stenosis can also occur as a result of rheumatic fever.
Mild aortic stenosis may produce no symptoms at all. The most common symptoms, depending on the severity of the disease, are chest pain, blackouts, and difficulty breathing. Using a stethoscope, a physician may hear a murmur and other abnormal heart sounds. An ECG, also called an electrocardiogram, records the electrical activity of the heart. This technique and chest x ray can show evidence that the left ventricle is enlarged.