Diagnosing Syncope

Healthcare providers giving cardiac stress test to woman on treadmill.Syncope is loss of consciousness (fainting). Your healthcare provider will ask you about your fainting episode and health history. You will also be examined. You will need multiple tests to evaluate your symptoms.

Health history and exam

You may be asked about:

  • Where and when you fainted, and how long you were unconscious

  • How you felt just before and right after you fainted

  • How you feel when you do activities like moderate to heavy exercise

  • Any family history of heart disease or fainting

  • Any cardiac or neurological problems you may have

  • Any medications you may be taking

  • If you drink alcohol or use illicit or recreational drugs

Your healthcare provider will examine you and may:

  • Check your blood pressure several times while lying down, sitting, and standing 

  • Listen for any heart murmurs or abnormal heartbeats

  • Listen and feel the pulses in your neck

  • Examine your eyes, reflexes, and limb movement


You may need 1 of more of the following tests:

  • Electrocardiogram (ECG). This can help your provider find a slow or a fast heartbeat.

  • Holter monitoring. You wear a portable ECG monitor for 24 hours. It records your heartbeat.

  • Event monitoring. You wear a portable ECG monitor for several weeks. It records your heartbeat.

  • Echocardiogram. This test takes pictures of your heart. It can show heart valve or heart function problems. Or it can reveal damage from a heart attack.

  • Electrophysiology studies (EPS). These help your provider find weak or damaged electrical pathways that make your heart beat too fast or slow. This helps your provider find the cause of a heart rate or rhythm problem and decide how to treat it.

  • Tilt table testing. Tilt table testing helps show if changes in your body position affect your heart rate and blood pressure.

  • Carotid artery ultrasound. This shows the blood flow through the arteries in the neck that supply oxygen and circulation to your brain. This test can locate any blockages in these arteries.

  • MRI or CT scan of the neck and brain. These tests can determine if there is something else going on in the brain that is causing a loss of consciousness by scanning the blood flow and brain structures. They are done in a radiology department.

  • Blood and other lab tests. These tests are used to find any abnormalities in your body that may cause syncope. For example, low blood sugar can cause a loss of consciousness which may be mistaken for syncope. Other wastes and toxins can affect the brains ability to function and affect consciousness.

  • Electroencephalogram (EEG). If your provider thinks you may be having seizures instead of syncope, this test may be done. Electrodes are applied to the scalp to measure the activity of the brain. A neurologist who specializes in reading EEGs would interpret the results.

You may be evaluated by a cardiologist, a neurologist, or an ear, nose, and throat specialist to fully evaluate the cause of your syncope. Treatment will be based on whatever the cause is. Be sure to ask your provider how you will receive the results of your tests and what additional steps must be taken.

One of the concerns with syncope is being injured from falling with a loss of consciousness. Finding a cause for syncope can help keep you safe from injury. Do not drive a car, operate heavy machinery, or engage in activities that may result in injury if you were to faint during the activity. Ask your provider when it will be safe for you to resume these activities.