Syncope is defined as transient loss of consciousness lasting for seconds to a few minutes with complete recovery. Only 70% of the fainting attacks are diagnosed despite thorough investigation. Out of these, 60% are due to vasovagal reflex, 30% are due to heart disorders and rest because of other reasons.
Vasovagal reflex is the most common cause of syncope, or in general terms is described as fainting attack by most of the patients. It can occur in any age group. They are usually precipitated by prolonged standing, dehydration, sight of blood, trauma or sometimes fear. Once this reflex is initiated, it causes drop in the heart rate and blood pressure, leading to decreased blood flow to the brain. Eventually patient becomes unconscious and falls on the floor following which they have profuse sweating and the body becomes warm. The episode usually lasts for 10-20 minutes with eventually complete recovery.
Various heart disorders are also responsible for fainting attacks and are usually found in old age. They occur suddenly and last for few minutes and are recurrent in nature. They can occur in any posture and may be preceded by a history of chest pain. Sometimes narrowing of the aortic valve leads to inability of the heart to supply blood to the brain, eventually causing them to faint.
Last but not the least, Transient Ischemic Attack (TIA) is also one of the causes of the fainting attack. There is transient decrease of blood flow to the brain because of obstruction in vessels supplying blood to the brain which recovers spontaneously.
MANAGEMENT: Almost 80% of these fainting attacks can be diagnosed by simply taking good history and a physical examination. Unfortunately most of the times the episode goes unnoticed because of lack of witness at the time of the event. Seldom we have got a detailed description of the episode.
Single episode does not require any investigation or treatment. Since most of these episodes are due to vasovagal reflex in which falling down is itself a kind of compensatory response of body to restore blood flow to the brain which can further be increased by raising the legs, they do not require further investigation or treatment. Of course, these attacks can be prevented by avoiding those circumstances which precipitate these episodes.
Cardiac or heart related syncopes can be investigated by doing electrocardiograph (ECG), 24hr ECG monitoring or by event loop recorder (ELR). Permanent pacemaker is usually the treatment of choice. Aortic valve replacement is required for narrowed aortic valve which can be picked up on echocardiography. Transient ischemic attacks can be treated with low dose aspirin.
Majority of fainting attacks are harmless which do not need treatment and should not become a cause of worry.