Tilt Table Testing
Tilt table testing is usually recommended for people who experience fainting (syncope) for an unknown reason and who do not have a structural heart disorder (such as narrowing of an aortic valve).
Typically, people are strapped to a motorized table and remain lying flat for 15 minutes. Then they are tilted head up at a 60° to 80° angle for 45 minutes to see whether they feel faint or their blood pressure and heart rate decrease. If blood pressure does not decrease, isoproterenol (a drug that stimulates the heart) is injected into the person's vein in a dose large enough to accelerate the heart rate by 20 beats per minute, and the test is repeated. Unfortunately, the procedure can sometimes indicate a heart disorder when none is present (a false-positive result).