Syncope is a temporary loss of consciousness and posture, described as "fainting" or "passing out." It's usually related to temporary insufficient blood flow to the brain.

Syncope can be caused by emotional stress, pain, pooling of blood in the legs due to sudden change in body position, overheating, dehydration, heavy sweating or exhaustion.

Some forms of syncope suggest a serious disorder:

• Those occurring with exercise
• Those associated with palpitations or irregularities of the heart
• Those associated with family history of recurrent syncope or sudden death.

The majority of children and young adults with syncope have no structural heart disease or significant arrhythmia, so extensive medical work-up is rarely needed.

A careful physical examination by a physician, including blood pressure and heart rate measured lying and standing, is generally the only evaluation required.

In other cases an electrocardiogram (EKG or ECG) is used to test for abnormal heart rhythms. If EKG and cardiac tests are normal, the person will undergo a tilt test.