Syncope or Fainting - Cardiac causes, symptoms, diagnosis & treatment

Syncope is a sudden, brief loss of consciousness or a fainting spell. Often it is due to insufficient flow of blood and oxygen to the brain. Often syncope is preceded by warning signs. These may include: seeing flashing or gleaming lights, having blurred vision or vision loss, having a sudden headache, neck or shoulder pain, feeling numb or weak, or having difficulty speaking.

Usually, if the syncope is caused by heart or cardiovascular problems, there will be no warning signs.

What causes syncope?
You may lose consciousness for a variety of reasons. Often the reasons are complex. Syncope may be a symptom of cardiac (heart) or noncardiac disease or be unrelated to illness.

Syncope may be a symptom of a serious disease which if left untreated may lead to permanent impairment. If you have fainted, be sure to contact your health care professional to obtain an accurate diagnosis and appropriate treatment.

Syncope is not only caused by an underlying illness. Fainting occurs on very rare occasions, as a result of stretching, coughing or other situations.

Some of the medical conditions of which fainting is a symptom are: disorders of the brain or nervous systems; disorders of the lungs, blood, heart or cardiovascular system; and psychiatric disorders such as hysteria or panic attacks. Two of the most common causes of syncope are "Vasovagal" syncope and "Orthostatic Hypotension."

What is Vasovagal syncope?
Vasovagal syncope accounts for about 50 percent of all episodes of fainting. Vasovagal syncope is an unusual response to emotional stress, excitement, fatigue, hunger or pain. Prior to fainting, you may feel lightheaded, nauseated, flushed, or warm. Your vision may dim and you may yawn. You may feel giddy.

If you have any of these warning signs, lie down. If you are having a vasovagal episode, lying down will alleviate the symptoms and may prevent fainting.

After fainting, you may be pale and have a slowed heart rate (bradycardia). This condition is temporary.

Your doctor may prescribe medication to prevent the recurrence of vasovagal syncope.

What is Orthostatic Hypotension?
Orthostatic hypotension or "postural syncope" is a potentially serious condition which occurs when your blood pressure significantly drops after you stand or sit up. If you experience orthostatic hypotension, you may feel dizzy or feel sudden neck or shoulder pain. You may also experience blurred vision prior to fainting.

If you have fainted due to orthostatic hypotension, you are probably at least 85 years old. Your chances of experiencing orthostatic hypotension are higher if you use anti-depressive or anti-hypertensive medications, if you have diabetes, Parkinson's disease or other conditions which affect the central nervous system; if you are dehydrated; or if you have been confined to bed for a long time.

Your doctor can treat orthostatic hypotension by treating the underlying illness or cause. She may change your current medication or prescribe medication and/or ask you to increase your intake of salt and fluids. She may tell you to wear elastic support stockings.

The following precautions may prevent postural syncope. Before arising from bed: exercise your legs briefly, sit on the edge of the bed to determine if you have any of the symptoms, then rise slowly.

Sleep with your head raised at least four inches. Eat small, frequent meals. Refrain from taking very hot showers or baths. Drink plenty of water. Limit your intake of alcohol.

Is syncope caused by cardiac arrhythmias?
Although certain irregular heart rates (arrhythmias) may cause syncope, fainting isn't inevitable if you have an arrhythmia. Your likelihood of fainting will increase if you have anemia, valvular heart disease or coronary artery disease. Your chances of fainting also go up if you have cerebrovascular disease which is damage to the vessels which supply blood and oxygen to the brain.

Some of the arrhythmias which may cause fainting are: atrioventricular block, sinus node disorder, ventricular tachycardia, paroxysmal atrial tachycardia, atrial fibrillation, or bradycardia.

Are there other cardiac conditions which are associated with fainting?
Syncope may be caused by the following cardiac conditions:

Massive acute myocardial infarction (heart attack);
Aortic stenosis - a narrowing of the heart valve that lies between the heart's left ventricle (lower chamber) and the aorta. This narrowing restricts blood flow to the body. Fainting usually occurs after exertion;
Pulmonary hypertension - a condition characterized by elevated pressure in the arteries that supply blood to your lungs;
Tetralogy of Fallot - a congenital condition that consists of four cardiovascular defects . Tetralogy of Fallot usually necessitates surgical correction; and
Carotid sinus sensitivity.

What is syncope due to carotid sinus sensitivity?
The carotid sinus is located in the carotid artery in your neck. In very rare cases, stimulation (through pressure or massage) of the carotid sinus will cause a drop in blood pressure and fainting.

If you experience syncope due to carotid sinus sensitivity, your doctor may recommend that you wear loose collars and that you turn your whole body (instead of merely your head), when looking to one side.

Are there other forms of loss of consciousness?
Sleep and coma and seizure are other forms of loss of consciousness.

If you have a seizure, you may experience a loss of consciousness which differs from syncope. A seizure is a convulsion that is caused by sudden abnormal electrical activity in the brain. Most often seizures are caused by epilepsy. Seizures vary in type. Some forms do not cause a loss of consciousness.

What are the differences between loss of consciousness due to syncope and that due to seizure?
You are more likely to injure yourself from a fall due to seizure than from one due to fainting, because your protective reflexes are still at work during syncope. Urination is more frequent with seizures. You will regain your consciousness faster if you have fainted than if you have had a seizure. Mental confusion, headache and drowsiness are more common after seizures than after syncope.

How will I feel when I revive from a faint?
You may not have any symptoms when you recover from a faint or you may have the one or more of the following: sweating, nausea, confusion, or pallor.

You probably will not recall having had presyncopal symptoms.

If I complain of fainting, what will my doctor do?
It is difficult but important for your doctor to distinguish syncope from other disturbances of consciousness (e.g. sleep, seizures), so that he may give you proper treatment.

Your doctor will take your medical history and perform a medical examination. As part of your history of fainting, he will be particularly interested in hearing bystander accounts.

Your doctor may order diagnostic tests. One test will probably be an echocardiogram. If your doctor suspects you have syncope upon exertion or if you have coronary artery disease, he may order exercise tolerance testing.

Additional diagnostic testing may include: angiographic studies, electrophysiology studies, Holter monitor testing or "event" testing. These last two tests enable your physician to get electrocardiographic readings that occur during your normal daily activities.

A major tool for diagnosing vasovagal syncope and defining susceptibility to orthostatic hypotension and other types of syncope, is "tilt table testing." During tilt table testing, you lie strapped to a table which can be moved slowly to a near upright position in order to bring on syncope. Your symptoms, heart rate and blood pressure are continuously monitored throughout the test.

What should I do if someone faints in my presence?
If someone near you complains of warning signs of syncope or actually faints, help her to lie down.. If that is not possible, have her sit up with her head lowered between her knees. Loosen all tight clothing and other constrictions. Turn her head so that her tongue does not fall back into her throat.

If possible, sprinkle or dash cold water on the person's face and neck or apply cold moist towels. If it is cold out, cover her body with a warm blanket.

Keep the individual lying down until her symptoms have disappeared. Have her rise slowly. Watch her for a few moments after she rises.