Syncope

Syncope is defined as a brief loss of consciousness with an inability to maintain postural tone that is followed by a rapid and complete recovery.

Syncope is common and about one-third of the population experiences a syncopal episode in their life. Syncope may be an alarming sign in some people who have a serious underlying medical condition. In a younger age group, more than 75% of cases are not associated with an underlying medical problem.

• Lightheadedness or dizziness
• Blurring of vision
• Heaviness in the lower limbs and swaying
• Loss of consciousness
• Drowsiness
• Pale skin
• Sweating
• Nausea

A number of causes can lead to syncope. To remain conscious, oxygen-rich blood must supply the brain without delay. A delay of blood to the brain for even 3-5 seconds can result in syncope.

Consciousness is regained after falling or lying down because blood returns to the brain once gravity is removed. A number of medical conditions can cause syncope.

The most common causes include:

 
A. Vasovagal Syncope

This is the most common type of syncope. This is triggered by a number of conditions including physical or emotional stress, fear (i.e. sight of blood), dehydration, bleeding, pain, anemia, fever, or fasting.

These conditions or ‘triggers’ stimulate a nerve to slow the heart rate and dilate the blood vessels, which causes blood to pool in the legs, resulting in low blood pressure (hypotension). This leads to a decrease or delay in blood flow to the brain resulting in syncope.

Symptoms include nausea, sweating, stomach pain, hyperventilation, weakness, and confusion.

B. Cardiac Syncope:

Cardiac syncope can be due to arrhythmia or obstruction to cardiac outflow.

• Alteration of the heart rate and rhythm can produce cardiac syncope. The heart rate and rhythm are controlled by the natural pacemaker of the heart known as the Sinoatrial Node.

This regulates the electrical activity of the heart which follows through a conduction pathway.

Syncope can occur due to problems at several places in this pathway.

When this is altered the condition is termed as arrhythmia.

Arrhythmias are produced by:

Other obstructive causes include mitral stenosis, pulmonary stenosis, pulmonary embolus, left atrial myxoma, and pericardial tamponade.

• Dr. Jamnadas  will ask of the events which occurred before, during, and after a syncopal attack.
• You will be asked of precipitating factors such as sleep or food deprivation, if you were in a warm atmosphere, if alcohol was consumed, if u had any pain, or had strong emotional stress before the occurrence of syncope.
• Warning signs before the attack might be discussed such as sweating or dizziness, which gives a clue towards a vasovagal syncopal attack.
• If the event was sudden without warning signs, it is more likely to be a heart rhythm problem.
• If the syncopal attack occurred during exertion, it is most likely an obstructive cause.
• If the event occurred after postural changes or standing for a long period of time.
• Details may be given from a witness present at the time of syncope and be able to estimate the duration of unconsciousness.
• A witness may also provide history of how you were after the episode. If postevent confusion was present, it is a clue to determining whether the episode was syncope or a seizure. Postevent confusion is suggestive of a seizure.
• You will also be asked if you have any preexisting medical conditions like heart disease or diabetes.
• History will be taken from patients who have taken medication prior to the event, including blood pressure lowering drugs.
• You will also be asked of any other personal and family history of cardiac disease.

• During a physical examination, your vitals will be taken. Vitals include taking your pulse, blood pressure, and temperature. Blood pressure may be taken more than once, in the laying and sitting position.
• Dr. Jamnadas will listen to the sounds of your heart to determine whether any high-grade valvular defects are present. They will also listen for any carotid artery bruits, indicating a narrowing of the blood vessel supplying the brain.
• Carotid sinus massage may be done. The carotid artery (artery in the neck) is firmly massaged while your heart rate is monitored. This can help in diagnosing a condition known as carotid sinus syncope.
• You will also be examined for any injuries that may have been sustained secondary to syncopes such as head injury, lacerations, or fractures.

• Blood Analysis– this includes a CBC to reveal signs of anemia, serum glucose levels, electrolytes and renal function tests. Cardiac enzymes may be checked in patients whom cardiac origin is high.
• Urine Analysis– to search for bacteria causing urinary tract infection, which may precipitate syncope.

• Electrocardiogram (EKG) – this is a common and easy test to perform which records the electrical activity of the heart. This detects any irregular heart rhythms and may show evidence of a preexisting heart attack.
• 24-Hour Holter monitor– records the electrical events of the heart during your normal daily activities. This helps in detecting signs of arrhythmias. It is important to accurately record your activities and symptoms so Dr. Jamnadas can compare them to the Holter monitor findings.
• Event monitor– If symptoms of arrhythmia are infrequent and do not occur within 24 hours, an event recorder may be ordered for you for up to 30 days.
• Echocardiogram (ECHO) – shows images of the heart determining the size and shape of the heart, and shows whether the heart walls and pumping activity are normal or performing weakly.
• Tilt Table Test– In this test you will be asked to lay flat on a table. The table will be tilted in various angles while your heart rate and blood pressure are monitored. This test is useful in revealing abnormal cardiovascular reflexes that produce syncope.
• Stress test– helps access the blood flow to the heart at rest and during stress. Will detect if any areas are receiving less blood flow.

• Chest x-ray– to assess the size and shape of the heart in congestive cardiac failure, infections within the lung causing pneumonia, or any fluid or mass can be seen in the lungs.
• Computerized tomography (CT scan) – to look for signs of abdominal aortic aneurysm or aortic dissection.
• T-wave alternans test (TWA)– detects abnormalities in electrical conduction that predicts sudden death.

• If you have carotid sinus syncope, you will be instructed to not wear tight collars, to use a razor instead of electric razor, and drink plenty of fluids.
• If you usually faint at the sign of blood, Lie Down immediately and elevate the legs once you feel any symptoms of syncope. If you are unable to lie down, sit down with your head between your knees.

• Fludrocortisone– can be given to increase the amount of blood volume.
• Midodrine– is a medication that can also be given to constrict the blood vessels to increase the blood volume.

Vasovagal syncope and orthostatic syncope have an excellent prognosis and do not increase the risk of death.

Patients with cardiac syncope may be restricted from their daily activities.

Without treatment, the prognosis for people with cardiac conditions is usually poor and has a mortality of 25%.

• Avoid standing up too quickly
• Sit near the aisle so you can leave if you feel faint
• Increase your salt and potassium intake
• Drink plenty of fluids
• Do not skip meals
• Do not stand for a long period of time
• Avoid alcohol and caffeine
• Review your medications with your doctor