Friday, October 29, 2010
POTS is easily misdiagnosed. The symptoms of postural orthostatic tachycardia often mimic other illnesses. There are a variety of tests that the POTS patient may undergo:
The tilt table test is the usual method used for detecting POTS. A patient is strapped to a table, which will tilt them upright at an angle of at least 60 degrees. Measurements of heart rate and blood pressure are taken while lying flat and then again at intervals while tilted upright. The normal duration of the test is 40 minutes or until they faint. Some patients are given a drug called isoproterenol through an intravenous line during this test. Other drugs that are sometimes used in place of isoproterenol include nitroglycerin, edrophonium, adenosine triphosphate, ephedrine and nitroprusside. These drugs are used to exacerbate POTS patients' symptoms and provoke syncope.
Magnetic resonance imaging (MRI) can also be used to diagnose some conditions like tumors, chiari malformation, cervical stenosis or the nutcracker phenomenon. The magnetic field and different radio frequencies allow detailed images to be generated.
A 24-hour urinary sodium test is handy in determining if one's plasma volume. It is important to determine patients' volume status and institute salt and fluid replacement in those with hypovolemia (or a low blood volume)
POTS patients also are subjected to a multitude of cardiac tests to ensure that their hearts are functioning properly. These tests include, but aren't limited to: wearing a Holter monitor, an Endless Loop monitor, an EKG, and stress tests.