Partial or complete loss of consciousness
Fainting (syncope) is the partial or complete loss of consciousness with interruption of awareness of oneself and ones surroundings.
When the loss of consciousness is temporary and there is spontaneous recovery, it is referred to as syncope or, in nonmedical terms, fainting.
Syncope accounts for one in every 30 visits to an emergency room. It is pronounced sin-ko-pea.
Syncope is due to a temporary reduction in blood flow and therefore a shortage of oxygen to the brain.
This leads to lightheadedness or a "black out" episode, a loss of consciousness.
Temporary impairment of the blood supply to the brain can be caused by heart conditions and by conditions that do not directly involve the heart.
Many non life-threatening factors, such as overheating, dehydration, heavy sweating, exhaustion or the pooling of blood in the legs due to sudden changes in body position, can trigger syncope.
several serious heart conditions, such as bradycardia, tachycardia or blood flow obstruction, can also cause syncope.
Heart failure, atrial fibrillation and other serious cardiac conditions can cause recurrent syncope in older adults, with a sharp increase after age 70.
Heart related causes may include an abnormal heart rhythm, problems with the heart valves or heart muscle and blockages of blood vessels from a pulmonary embolism or aortic dissection among others.
Neurally mediated syncope occurs when blood vessels expand and heart rate decreases inappropriately. This may occur from either a triggering event such as exposure to blood, pain, strong feelings or a specific activity such as urination, vomiting, or coughing.This type of syncope may also occur when an area in the neck known as the carotid sinus is pressed.
The third type of syncope is due to a drop in blood pressure from standing up
