If you have episodes of fainting, your doctor will first want a complete description of the symptoms and events surrounding these episodes. For instance, the doctor may ask:
Do these episodes come on suddenly or gradually?
Are you standing, sitting, or lying down when you faint?
Do you notice any other symptoms?
How long does the episode last?
Do you return to normal quickly after fainting, or are you momentarily confused?
Your doctor may attempt to reproduce the symptoms by simulating the situation during which you usually have a fainting episode. For example, if you tend to faint after coughing, you may be asked to bear down forcibly, in order to see if this causes symptoms. You may have your pulse and blood pressure taken lying down and then again after quickly standing, in order to see what changes are provoked by these different positions.
This may be all the evaluation performed in an otherwise healthy child or young adult. But in some cases, your doctor may want to evaluate you further for a heart or brain problem.
The heart evaluation usually starts with an electrocardiogram (ECG), which measures the electrical activity of your heart to look for heart arrythmias. Other tests, such as an exercise stress test, Holter monitor, or echocardiogram may be needed to rule out other cardiac causes of fainting.
If ECG and other heart tests are normal but your doctor still suspects a heart abnormality, he may order what's called a tilt-table test. A tilt-table test is often used because some people have preliminary symptoms of fainting or actually do faint from having their heads and bodies tilted to about 60 or 70 degrees. Someone may faint during the tilt, due to the rapid drop in blood pressure and/or heart rate. As soon as the person is placed on his back again, blood flow and consciousness are restored.
If your doctor suspects that your fainting is due to a seizure, he may order an electroencephalogram (EEG), which records the activity of your brain waves.