Tilt Table Testing

Many patients who "pass out" do so because of problems with the reflexes that control blood pressure. Pooling of blood in the veins of the legs and abdomen with upright posture can result in drops in blood pressure and symptoms of lightheadedness or syncope. Tilt table testing can be used to provoke syncope in a controlled setting in order to see if this mechanism explains why someone is passing out. The test involves placing the patient on a special table and standing him or her upright at 60 to 70 degrees for 30 to 45 minutes. The subject is unable to move his legs during the test so that blood is not actively pumped up to the thorax. Blood is thereby allowed to pool in the legs, so that other reflexes must be activated to keep the blood pressure from falling. If these reflexes cannot compensate for the decrease on venous return, the blood pressure falls. If the blood pressure falls sufficiently, the patient may pass out. Blood pressure and heart rhythm are monitored continuously during the test. An intravenous line is inserted before the test starts so that IV fluids or medications can be given during the test.

During tilt table testing, some people experience no symptoms. Other people may feel nauseated or sweaty, and others may pass out completely. The test involves no serious risks. Testing can be performed in the hospital or in an office setting.