What is syncope? Syncope (pronounced “sin ko pea”) is the medical term for fainting or passing out. It is caused by a temporary drop in the amount of blood that flows to the brain. Syncope can happen if you have a sudden drop in blood pressure, a drop in heart rate, or changes in the amount of blood in areas of your body. If you pass out, you will likely become conscious and alert right away, but you may be feel confused for a bit. Autonomic Nervous System (ANS) The ANS automatically controls many functions of the body, such as breathing, blood pressure, heart rate and bladder control. Most times, these things happen without us noticing.