Presyncope is a state consisting of lightheadedness, muscular weakness, blurred vision, and feeling faint (as opposed to a syncope, which is actually fainting). Presyncope is most often cardiovascular in etiology. In many patients, lightheadedness is a symptom of orthostatic hypotension. Orthostatic hypotension occurs when blood pressure drops significantly when the patient stands from a supine or sitting position. If loss of consciousness occurs in this situation, it is termed syncope.
The tilt table test is an evaluative clinical test to help identify postural hypotension, a common cause of presyncope or syncope. A tilt angle of 60 and 70 degrees is optimal and maintains a high degree of specificity. A positive sign with the tilt table test must be taken in context of patient history, with consideration of pertinent clinical findings before coming to a conclusion.
^ abNatale, A., Akhtar, M., Jazayeri, M., Dhala, A., Blanck, Z., Deshpande, S., et al. (1995). Provocation of Hypotension During Head-Up Tilt Testing in Subjects With No History of Syncope or Presyncop. American Heart Association, (92), 54-58. doi: 10.1161/01.CIR.92.1.54; url: http://circ.ahajournals.org/content/92/1/54.full