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Determining Why You’re Fainting

Fainting (Unexplained)

There are many tests your healthcare team can perform to find out what is causing your fainting.

An initial evaluation commonly includes:


Physical Examination and Medical History – You’ll be asked for your fainting symptoms during a thorough physical examination.

Screening Tilt Table Test – During a tilt table test, you will lie on a table that tilts by varying angles and will be connected to a machine that allows your doctor to measure how your blood pressure, heart rate, and heart rhythm respond to changes in body position. This procedure takes about two hours.

Blood Volume Determination – An intravenous (IV) line will be inserted into a vein in your arm and a substance will be injected. Blood samples will be taken. This test is used to evaluate if the amount of blood in your body is right for your gender, height, and weight.

Hemodynamic Testing – Images are taken after a substance has been injected into the IV. This test evaluates the blood flow and pressure when the heart muscle contracts and pumps blood throughout your body.

Autonomic Reflex Testing – A series of tests will monitor your blood pressure, blood flow, heart rate, skin temperature, and sweating in response to stimuli. This helps determine if your autonomic nervous system is functionally normally.

Other tests, like those listed below, may be necessary. These tests allow your healthcare team to view your heart rhythms before or after fainting or in conditions similar to fainting. This way, your doctor can better determine if your fainting is caused by a cardiac condition.

Echocardiogram – A device called a transducer is placed on your chest and sound waves are bounced off your heart. This provides a “moving” picture of your heart, heart valves, and how your heart is pumping.

Electrocardiogram (ECG) – This test records your heart’s electrical activity using electrode patches with wires attached to them that are placed on your chest, arms, and legs. The wires are connected to a monitor that captures the ECG. The test takes a few minutes.

Electroencephalogram (EEG) – This test will record your brain wave activity to help determine where seizures may occur.

Electrophysiology (EP) Study – Catheters are threaded into your heart to reproduce abnormal heart rhythms and extra heartbeats so your heart’s electrical impulses and responses to the heartbeats can be evaluated. The procedure lasts about two hours.

External Loop – After a fainting episode, you press a button on the recorder to evaluate the heart’s activity. The recorder is worn on the wrist or around the waist for several days or up to one month.

Holter Monitor – Using electrode patches placed on your chest, this test measures and records your heart’s electrical activity. The patches have wires attached to them and are connected to a portable monitor about the size of a small tape recorder. The Holter monitor is worn for one to two days.

Medtronic Reveal LINQ™ Insertable Cardiac Monitor – This is an insertable device that monitors heart rhythms automatically or by using a patient activator. Smaller than a key, the device is implanted in a simple outpatient procedure, and can remain inserted just beneath the skin in the upper chest area for up to 3 years.*

Stress Test – This test is performed while you exercise to measure how your heart functions when there is an increase in the body’s demand for oxygen.

Information on this site should not be used as a substitute for talking with your doctor. Always talk with your doctor about diagnosis and treatment information.