The use of head-up tilt table testing in the evaluation of unexplained syncope.

Head-up tilt table testing was performed in 50 patients for evaluation of syncope. A positive test occurred in 29 patients (58 percent). Of these 29 patients, 15 were categorized as vasovagal; 11 as orthostatic hypotension; and three as chronotropic incompetence. Isoproterenol facilitated the occurrence of a positive test in 13 patients. Medications were used to treat 15 of the 29 patients having a positive test result. Syncope recurred in two patients over a 9 +/- 5 month follow-up period. In patients having unexplained syncope, head-up tilt table testing may provide a diagnosis and can be used to assess therapy. Earlier use of this testing modality in selected patients may obviate more expensive testing.