Syncope is a common disorder of temporary loss of consciousness and posture, described as ‘fainting’ or ‘passing out.’ It’s usually related to temporary insufficient blood flow to the brain and annually affects six per cent of elderly persons and accounts for 3 per cent of emergency department visits. Syncope is an important heart problem, is disabling, costly, may cause grievous injury or may be the only initial sign before the sudden cardiac death. Evaluating cause of syncope is difficult as brain, heart or some metabolic abnormality could be responsible for the same. The probable cause of syncope is established in only 75 per cent of cases. The annual cost of evaluating and treating patients with syncope in United States alone is a staggering 800 million dollars.
The common faint or Vasovagal Syncope
Most of us remember that in our morning school assembly, a student would fall on prolonged standing. On lying flat on the ground he would recover promptly and such episodes were more common during sunny days. This was actually vasovagal syncope or the common faint. This is more common during emotional stress, pain, after a hot shower or in warm environment. It is seen mostly in young women and is more often than not associated with warning symptoms such as nausea, blurred vision or light-headedness. But there are many more forms of syncope, with many causes, apart from the vasovagal syncope.
Tilt table testing and other tools
The gold standard test for the diagnosis of the common faint is tilt table test. This is a simple non-invasive method for recognition of this condition. Keeping the patient in upright position for 30 to 45 minutes at an angle of about 70 degrees performs this test. The test is done on a special mechanized examination table with safety belts and footrest. Sometimes an additional drug is given to enhance the positivity of the test. The positivity of the test is defined as development of syncope or slow heart rate with drop in blood pressure. The syncope observed is usually reversible on making the table horizontal or after giving additional drugs to the patient. The test is generally performed in a susceptible population where recurrent disabling syncope episodes or a single episode has occurred. But in presence of organic heart disease the test is contraindicated.
Other investigating tools for the diagnosis of syncope include careful history taking, holter monitoring, echocardiography, stress testing, signal averaged ECG, event recorder and electro physiology testing. A proper neurological examination completes the appropriate workup for this condition.
The treatment depends on the cause discovered and may include appropriate patient education, increase in salt intake, discontinuation of an offending drug, starting a new drug, pacemaker or AICD implantation and catheter ablation. The latter modalities are performed in specialized centers and are expensive. Cardiac syncope has a poorer prognosis than other forms of syncope. The one year end pint mortality rate has been shown to be as high as 18-33 per cent. Non-cardiac including vasovagal syncope seems to have no effect on overall mortality rates. Patients with syncope should be instructed not to drive until curative treatment has been done.