All fainting spells require consultation, although brief periods of un¬consciousness are usually not serious. Prior to fainting, a child may feel light¬headed and nauseated; then he/she will be-come limp and fall to the floor.
In children, most common cause of fainting episodes is due to vasovagal syncope. These episodes typically take place when there is temporarily an inadequate supply of blood and oxygen to the brain, often related to stress, fear, or overexertion, long standing etc. Hot weather, pain, an empty stomach, or a peculiar odor can also sometimes cause a child to faint.
Generally, fainting spells last for just a minute or less, after which normal blood flow returns and the child regains con¬sciousness. Until then, keeps your child lying down with his/her feet slightly ele¬vated.
Some fainting episodes require immedi¬ate attention. A weak pulse or shallow breathing requires emergency care.
It can be due to heart related also. It can either due to abnormal heart beat or cardiac rhythm or can be due to severe obstruction at the level of aortic valve (severe aortic stenosis) that leads to low cardiac output with less blood supply to the brain.
It needs to address urgently by consulting pediatric cardiologist.
ECG and echocardiogram are must for diagnosing the heart rhythm abnormalities along with assessment of structural cardiac diseases. Sometimes, Holter monitoring is also required for detection of heart rhythm abnormalities.