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 and often occurs when the the heart doesn't pump a normal supply of oxygen to the brain or blood pressure is too low.

Syncope

Syncope, or fainting, is the temporary loss of consciousness resulting from a sudden decline in blood flow to the brain. It can be caused by a variety of things, but where a cardiologist of electrophysiologist is concerned, it results from an irregular cardiac rate or rhythm or by changes of blood volume or distribution.

What causes Syncope?

It may be caused by emotional stress, pain, pooling of blood in the legs due to sudden changes in body position, overheating, dehydration, heavy sweating or exhaustion. Non-cardiac syncope is treated by having the patient lay down with the legs elevated. Infrequent episodes of non-cardiac syncope usually do not require treatment.

Syncope links
American Heart Association - SCD

National Center for Early Defibrillation

Emedicine.com - SCD

Heart Rhythm Society

Cardiac syncope is another matter.

Cardiac syncope may occur during violent coughing spells (especially in men) because of rapid changes in blood pressure. It also may result from several heart, neurologic, psychiatric, metabolic and lung disorders. And it may be a side effect of some medicines.

Cardiac syncope suggests a serious disorder and is best described as one of the following

  1. fainting associated with palpitations or irregularities of the heart; or,
  2. fainting associated with family history of recurrent syncope or sudden death;
  3. fainting occurring with exercise; or
  4. fainting occuring suddenly without warning.

Treatment

The majority of people with syncope have no structural heart disease or abnormal heart rhythm so correct diagnosis is essential in determining possible treatments. A careful physical examination by a physician, including blood pressure and heart rate measured lying and standing, is generally recommended as a first step.

If the initial evaluation reveals something, a cardiologist or electrophysiologist will often perform an exercise stress test, Holter monitor, echocardiogram or electrocardiogram to test for abnormal heart rhythms.

If tests seem to indicate heart rhythms are are normal, the doctor might also suggest a "tilt" test, in which a patient's blood pressure and heart rate will be measured while he or she is lying down on a board/table; after the measurement, the board is tilted up. Someone who has neuro- cardiac syncope will usually faint during the tilt, due to the rapid drop in blood pressure and heart rate. As soon as the person is placed on his or her back again, blood flow and consciousness are restored.

To help prevent syncope, people with neuro- cardiac syncope should be on a high-salt diet and drink plenty of fluids to avoid dehydration and maintain blood volume. They should watch for the warning signs of fainting -- dizziness, nausea and sweaty palms -- and sit or lie down if they feel the warning signs. Some people also may need medication.