Syncope is most commonly described as “fainting,” or “passing out.”  It is the temporary loss of consciousness and posture, usually due to momentary insufficient blood flow to the brain and can occur in otherwise healthy people. Syncope can result when blood pressure is too low (hypotension), such that the heart isn’t pumping a normal supply of oxygen to the brain.

More than three percent of emergency room visits and six percent of hospital admissions are due to this type of non-cardiac syncope. Another type, more common to children and young adults, is called neurally mediated syncope (NMS), otherwise known as neurocardiogenic, vasovagal, vasodepressor or reflex mediated syncope. While syncope alone is not life threatening, it may sometimes be a symptom of a more serious condition that could be life threatening and should be treated promptly.

About 30 percent of people who experience one episode of syncope will have a recurrence. The underlying cause of syncope and the patient’s age, gender and presence of other medical conditions will affect the course of treatment and methods of prevention.

When to Call Your Doctor
Symptoms
Causes
Prevention
Diagnosis
Treatment

When to Call Your Doctor
Infrequent episodes generally do not require treatment. Full recovery can be made after a few minutes of lying down with your legs elevated. However, your physician should evaluate you if you experience frequent syncope, as it may be a symptom of another medical condition.

Symptoms
Patients may feel faint (especially following a meal or exercise), dizzy or lightheaded (presyncope). Unsteadiness or feeling weak when standing are signals syncope may occur.

Premonitory symptoms (those which precede syncope) include lightheadedness, nausea and irregular heartbeat that is sometimes described as “fluttering” in the chest. You can control a “syncopal event” by learning the signs and sitting or lying down and elevating your legs as soon as those signs present themselves.

Causes
Changes in the amount of blood being distributed or any type of interruption in blood circulation can cause syncope. Syncope may occur due to an irregular cardiac rate or rhythm, metabolic abnormalities or anemia.

• Head injury.
• Epilepsy.
• Stroke.
• Inner ear problems.
• Dehydration.
• Low blood sugar.
• Breath-holding episodes.

In about one-third of cases, the cause of syncope is unknown.

Prevention
Those with NMS can take some prevention measures that include a high-salt diet and plenty of fluids to avoid dehydration and maintain blood volume. They should also be prepared to recognize the warning signs of fainting and respond to them quickly by sitting or lying down. Some cases of syncope may require medication.

Diagnosis
In addition to having your blood pressure and heart rate measured while you are lying flat, sitting up and standing, you may undergo several tests to determine the underlying causes of syncope. These tests could include:

• Blood tests. Low blood sugar and dehydration can be measured.
• Electrocardiogram. An ECG or EKG records the electrical activity of the heart and shows abnormal rhythms (arrhythmias or dysrhythmias).
• Tilt table test. This test is designed to record your blood pressure and heart rate on a minute-by-minute or beat-by-beat basis while the table is tilted at different levels. In some patients, this test may reveal abnormal cardiovascular reflexes that produce syncope.
• Echocardiogram. An “echo” uses ultrasound waves to produce a moving picture of the heart and heart valves.

Treatment
Syncope can be managed and controlled once it has been correctly diagnosed. Generally, treatment is directed at preventing recurring syncope and may include:

• Medications.
• Support garments to improve circulation.
• Dietary changes.
• Sleep changes, such as elevating your head at night with extra pillows.
• Avoiding syncope triggers.
• A pacemaker, for severe medical conditions causing syncope.
• An implantable cardioverter defibrillator (ICD), which monitors your heart rate and corrects rapid or abnormal rhythms.

Some states require that patients diagnosed with syncope notify the state’s motor vehicle administration. Check your state’s regulations for more information.