What is Syncope?

Syncope (pronounced "sin-ko-pea") is the brief loss of consciousness and posture caused by a temporary decrease in blood flow to the brain. Syncope may be associated with a sudden fall in blood pressure, a decrease in heart rate, or changes in blood volume or distribution. The person usually regains consciousness and becomes alert right away, but may experience a brief period of confusion.

Syncope is a common condition, affecting 3 percent of men and 3.5 percent of women at some point in life. It becomes more prevalent with advancing age, occurring in as many as 6 percent of people over age 75. Syncope affects patients of all ages, both with and without other medical conditions.

Syncope is often the result of an underlying medical condition that could be related to your heart, nervous system, or blood flow to the brain.

With accurate diagnosis and appropriate treatment, syncope can be resolved in most patients.

What are the Symptoms?

The symptoms of syncope include one or more of the following:

• "Blacking out"
• Light-headedness
• Falling for no reason
• Dizziness
• Drowsiness
• Grogginess
• Fainting, especially after a meal or after exercise
• Feeling unsteady or weak when standing

Syncope is often preceded by other symptoms (called premonitory symptoms), such as lightheadedness, nausea, and palpitations (irregular heartbeats that feel like "fluttering" in the chest).

Many people with syncope learn, on their own, to avoid a syncopal event or "passing out." They recognize the premonitory symptoms and sit or lie down quickly and elevate their legs. Because syncope can be  sign of a more serious condition, it is important to seek treatment right immediately after a syncope episode occurs.

What Causes Syncope?

Autonomic Nervous System (ANS)
 
The ANS automatically controls many functions of the body, such as breathing, blood pressure, heart rate, and bladder. In most situations, we are unaware of the workings of the ANS because it functions in an involuntary, reflexive manner. 
 
There are many causes of syncope. If blood does not circulate properly, or the autonomic nervous system does not work the way it should, changes in blood pressure and heart rate can cause fainting. Metabolic abnormalities and anemia may also cause syncope.

Types of syncope include:

• Vasovagal syncope (also called cardioneurogenic syncope): most common type of syncope that occurs when the blood pressure drops suddenly, reducing blood flow to the brain. When you stand up, gravity causes blood to settle in the lower part of your body, below the level of the diaphragm. In response, the heart and autonomic nervous system (ANS) react to maintain your blood pressure.

Vasovagal syncope may occur in patients who have a condition called orthostatic hypotension. In this condition, the blood vessels do not constrict normally when the patient stands, causing blood to pool in the legs and the blood pressure to drop quickly.

• Situational syncope: a type of vasovagal syncope that occurs only during particular situations that cause unusual patterns of stimulation to certain nerves. The “stimulus” that triggers an exaggerated neurological reflex can be a wide range of different events such as dehydration, intense emotional stress, anxiety, fear, pain, hunger or use of alcohol or drugs. Hyperventilation (breathing in too much oxygen and getting rid of too much carbon dioxide too quickly) associated with panic or anxiety also can cause syncope. Other stimuli include coughing forcefully, turning the neck or wearing a tight collar (carotid sinus hypersensitivity), or urinating (miturition syncope).

• Postural syncope (also called postural hypotension): occurs when the blood pressure drops suddenly due to a quick change in position, such as from lying down to standing. Postural syncope can be related to certain medications or dehydration.

• Cardiac syncope: loss of consciousness due to a heart or blood vessel condition that interferes with blood flow to the brain. These conditions may include an abnormal heart rhythm (arrhythmia), obstructed blood flow in the heart or blood vessels, valve disease, aortic stenosis, blood clot, or heart failure.

• Neurologic syncope: loss of consciousness due to a neurological condition such as seizure, stroke, transient ischemic attack (TIA) or other rare causes including migraines and normal pressure hydrocephalus.

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

How is Syncope Diagnosed?

All patients with syncope should be evaluated by a doctor. Your primary care physician can provide a referral to the MetroHealth Heart & Vascular Clinic for a complete evaluation to determine the cause of your syncope.

The syncope evaluation begins with a careful review of your medical history and a physical exam. The doctor will ask you detailed questions about your symptoms and syncope episodes, including whether you have any premonitory symptoms and the circumstances in which your symptoms occur.

Your heart rate and blood pressure will be measured and recorded while you are in different positions including lying down, sitting, and standing.

Test to Determine Causes of Syncope

• The head-up tilt test or tilt table test : records your blood pressure and heart rate on a minute-by-minute or beat-by-beat basis while the table is tilted in a head-up position at different levels. In some patients, this test may reveal abnormal cardiovascular reflexes that produce syncope.

• Holter monitoring
• Electrophysiology studies
• neurological evaluation
• computed tomography scan
• Echocardiogram
• Vestibular function testing by an ear, nose and throat (ENT) doctor, may be performed to rule out the presence of inner ear problems.

If any of these tests are ordered, your doctor will explain why they are needed and what will happen during the test.

How is Syncope Treated?

Depending on the results of your evaluation and the underlying cause of syncope, treatment is aimed at preventing a syncope recurrence.

Treatment May Include:

• Taking new medications or making changes to your current medications

• Wearing support garments or compression stockings to improve circulatio n

• Making certain dietary changes such as eating small, more frequent meals; increasing salt, fluid and potassium; and avoiding caffeine and alcohol

• Taking certain precautions when changing positions from sitting to standing

• Elevating the head of your bed while sleeping. You can do this by using extra pillows or by placing risers under the legs of the head of the bed to elevate it. 

• Avoiding or changing the situations or "triggers" that cause a syncope episode

• Biofeedback training to control a rapid heartbeat.

• Pacemaker implantation to regulate the heart rate -- only as needed for certain medical conditions

• Implantable cardiac defibrillator (ICD), which constantly monitors your heart rate and rhythm and corrects a fast, abnormal rhythm -- only as needed for certain medical conditions

Your health care team will develop a treatment plan that is right for you and your doctor will discuss your treatment options.

Some states require that patients diagnosed with syncope notify the state's drivers license bureau. Check your state's regulations to be sure.

About 30 percent of people with one episode of syncope will have a recurrence. The underlying cause of syncope and the patient's age, gender, and other co-existing medical conditions will affect the prognosis or outlook.

With the proper diagnosis and treatment, syncope can be managed and controlled. The prognosis or outlook for the future is dependent on the underlying cause of syncope.