What is Syncope?
Syncope is a medical term for “fainting” or “passing out.” Syncope is common in otherwise healthy children and adolescents but can affect all age groups. Syncope (pronounced: sĭng’-kə-pē) occurs at least once during childhood in more than 15 percent of youth, especially teenagers. About one-third of us will faint at least once during our lifetime.
Syncope is caused by a sudden drop in heart rate and blood pressure, which reduces blood flow to the brain. It occurs when the body overreacts to triggers, such as prolonged standing in hot and humid weather, the sight of blood, or extreme emotional distress. If a person is about to faint, he or she will feel dizzy, lightheaded, or nauseous and their field of vision may “white out” or “black out.”The skin may be cold and clammy. The person drops to the floor as he or she loses consciousness.Once the person is horizontal on the ground, blood returns to the heart and brain, and he or she quickly regains consciousness and returns to normal.
What are common symptoms? How does this problem present?
Before a faint due to vasovagal syncope occurs, a child may experience some of the following symptoms:
The most common symptoms of syncope include:
Are there any known causes?
There are three types of syncope:
Neurally mediated syncope or Vasovagal syncope: most common and usually harmless
Orthostatic syncope: very rare in otherwise normal small children
Cardiac syncope: rare but potentially life-threatening
What is vasovagal syncope?
Vasovagal syncope is the most common cause of fainting and often affects young, healthy people who have no history of heart disease or neurological problems. It is generally thought to result from a "miscommunication" between the brain and the heart or an exaggeration of a normal reflex. Vasovagal syncope occurs when the part of the nervous system that regulates heart rate and blood pressure malfunctions in response to a trigger, such as the sight of blood. The heart rate slows, and the blood vessels in the legs widen. This allows blood to pool in the legs, which lowers the blood pressure. This drop in blood pressure and slowed heart rate quickly diminish blood flow to the brain, and fainting occurs.
Less commonly, syncope may occur during the brushing of one's hair (“hair-groomer's syncope”), vigorous arching of the back, and extending the neck while stretching (“stretch syncope”), urination (“micturition syncope”), and even while chewing food (“deglutition syncope”).
“Pallid breath-holding spells” are a form of vasovagal syncope that affects toddlers in response to sudden fright, frustration, or mild head trauma.
Vasovagal syncope is usually harmless and requires no treatment. However, children can injure themselves during a vasovagal syncope episode.
Common triggers for vasovagal syncope include:
What is cardiac syncope?
On rare occasions, syncope can also be a symptom of heart disease or abnormalities. Cardiac syncope during childhood is rare but is the most worrisome because it can be life-threatening.
Some examples of cardiac-related causes of syncope are:
Secondary to obstruction to blood flow (aortic valvular stenosis, hypertrophic cardiomyopathy, primary pulmonary hypertension, Eisenmenger's syndrome)
Heart rhythm abnormalities (ventricular tachycardia, Wolff-Parkinson-White syndrome, long QT syndrome, sinus node dysfunction, atrioventricular block, arrhythmogenic right ventricular dysplasia)
Diminished heart function (ventricular dysfunction from a variety of causes including dilated cardiomyopathy; inflammatory diseases such as acute myocarditis and Kawasaki disease, and ischemic heart disease secondary to an anomalous coronary artery)
What kind of testing and diagnostic tools are used to determine diagnosis or disease?
All patients with syncope should be evaluated by a primary care provider. The purpose of the evaluation is to rule out dangerous causes of your child's fainting, particularly heart-related problems.
In addition to a detailed history and physical examination, your child will need an electrocardiogram (ECG). This test records the electrical signals your heart produces. It can detect irregular heart rhythms and other cardiac problems that can cause fainting. With a detailed history, thorough physical examination, and ECG, your physician can accurately diagnose vasovagal syncope.In addition to the ECG, the pediatric cardiologist may decide to perform the following additional tests:
Event or Holter monitor: These are portable monitors that are placed for at least a 24-hour period or as long as a month. These monitors record the electrical signals the heart produces. They can detect irregular heart rhythms and other cardiac problems that can cause fainting.
Echocardiogram: An ultrasound of the heart, which uses ultrasound imaging to view the heart and look for conditions, such as valve problems, that can cause fainting.
Exercise stress test: This test studies heart rhythms during exercise. It is usually conducted while the child walks or jogs on a treadmill.
Tilt table test: If there appear to be no heart problems causing your fainting, your doctor may suggest your child undergo a tilt table test. For the test, the child will lie flat on his or her back on a table. The table changes positions, tilting the child upward at various angles. We monitor the child's heart rhythm and blood pressure during the test to see if the postural changes affect them.
Implantable Loop Recorder: Very rarely, a pediatric cardiologist who specializes in rhythm problems in children or a pediatric electrophysiologist may decide to implant a small recording device under the skin with a minor same-day surgical procedure. This device can monitor the heart rhythm for up to three years and may provide helpful information regarding the rhythm abnormality at the time of fainting, and may guide further treatment.
When do these symptoms require care from someone who specializes in children's heart disease?
In some circumstances your primary care provider will make a referral to a pediatric cardiologist for a complete evaluation and management of your child's syncope.
Examples of symptoms that require care from a pediatric cardiologist:
Fainting that occurs during physical exertion, especially when in motion. There may be a more serious cause for the fainting, and the fainting may be due to a primary heart condition
Heart racing or chest pain is experienced before fainting
Syncope/ fainting without any forewarning
Past heart problems, abnormal cardiac examination, and abnormal ECG
Family history of sudden death at young age, deafness, seizures or unexplained drowning
Anyone with a family history of inherited heart electrical problems, such as long QT syndrome or inherited heart muscle problems, such as hypertrophic cardiomyopathy
The pediatric cardiologist will be able to determine whether a patient's complaint of syncope and/or dizziness has a life-threatening cause. The child's description of his/her symptoms (history) is the most important part of the evaluation. If possible, have an eyewitness accompany your child for the doctor's visit to help explain the incident.
Both cardiac and neurologic causes of syncope can usually be excluded with a good history and physical examination.
What are possible treatment options?
In most cases of vasovagal syncope, treatment is unnecessary.
The immediate treatment for a child who has fainted involves checking first to see if they are breathing.The child should remain lying down for at least 10-15 minutes, preferably in a cool and quiet space.If this is not possible, have the child sit forward and lower their head below their shoulders and between their knees.Complete recovery can usually be expected within a short period of time.
For children who have problems with chronic fainting spells, therapy should focus on recognizing the triggers and learning techniques to prevent fainting.
At the appearance of warning signs such as lightheadedness, nausea, or cold and clammy skin, counter-pressure maneuvers that involve gripping fingers into a fist, tensing the arms, and crossing the legs or squeezing the thighs together can be used to ward off a fainting spell.
Wearing elastic stockings
Increasing salt in the diet (if the child does not have high blood pressure)
Avoiding prolonged standing especially in hot, crowded places
Drinking plenty of fluids. Fluid intake should be increased to the point that one's urine is colorless.
If your child experiences vasovagal syncope often enough that it interferes with his/her quality of life, your doctor may suggest trying one or more of the following remedies:
Medications: Drugs that may help prevent vasovagal syncope include:
- Common medications for children with neurally mediated syncope. This type of medication works by helping the kidneys retain fluid and sodium. Rare side effects include minimal weight gain, excessively high blood pressure (hypertension), and leg cramping. Leg cramping is caused by low potassium.
- Blood vessel constrictors. Drugs to treat low blood pressure are sometimes helpful in preventing vasovagal syncope
In a very few select patients, the insertion of an electrical pacemaker, which helps regulate the heartbeat, may help with vasovagal syncope.
Cardiac syncope may be controlled by treating the heart defect involved. For example, arrhythmias may be treated with medications, with the insertion of a pacemaker, or with other procedures.
What happens after treatment? Will my child require care throughout childhood/adulthood? What is the prognosis?
Most patients with neurally mediated syncope will eventually outgrow their symptoms, though this may take several years.
Most common questions about syncope:
Is syncope life threatening?
Vasovagal syncope is not life threatening. However, one can injure himself or herself during a vasovagal syncope episode. Cardiac syncope can be life threatening.
When should my child see a physician?
All patients with syncope should be evaluated by a primary care provider. The purpose of the evaluation is not only to diagnose vasovagal syncope but to rule out other possible causes of fainting, particularly heart-related problems.
To make an appointment with the Children's Heart Program, please call 410-328-4FIT (4348) or 1-800-373-4111 (referring physicians only).