How is fainting related to left ventricle outflow tract obstruction?

Left ventricle outflow tract obstruction can cause fainting due to an inability of blood to adequately leave the main pumping chamber of the heart (the left ventricle) to travel to the body. The blockage may occur within the main pumping chamber, below the outlet (the aortic valve), at the level of the aortic valve or above the level of the valve. It can be worsened with exercise or activities that make the heart work harder. It can come on quickly, sometimes with chest pain and shortness of breath. If severe, this kind of obstruction can increase the risk of developing a serious heart rhythm abnormality (called an arrhythmia). This kind of fainting is considered to be an indication of a serious heart problem. Any episode of unexplained fainting should be evaluated by your physician in order to exclude the possibility of a more serious condition.