THE VALUE OF TILT-TABLE TESTING WITH ISOPROTERENOL IN DETERMINING THERAPY IN ADULTS WITH SYNCOPE AND PRESYNCOPE OF UNEXPLAINED ORIGIN

Background: Previous studies have shown the effectiveness of tilt table testing in establishing the diagnosis of neurocardiogenic syncope and in dictating therapy in patients with syncope of unknown origin. Most studies have been limited by small numbers of patients and brief followup. Tilt table testing was performed with and without isoproterenol hydrochloride in 94 patients, and therapy was determined by the test findings. The patients were followed up for at least 10 months (mean, 17.8 months). Methods: The 80 degrees tilt table test was performed in 94 consecutive patients who presented with syncope (n=74) or presyncope (n=20) and in whom neurologic and cardiac causes were ruled out. Therapy was determined by the tilt test findings. Sixty-seven patients were followed up for 17+/-5.3 months (mean+/-SD) (range, 10 to 27 months). Results: Forty-nine patients had positive results of tilt studies and received therapy. Of these 49 patients, 36 returned for second tilt studies while they were taking medication, and 30 had negative results. Six patients had medication changes and had negative results of follow-up tilt studies. No symptoms were noted on follow-up in the 24 patients who presented with syncope and who had positive results of tilt tests that responded to therapy. Of those 35 patients presenting with syncope who had negative results of initial tilt studies and who did not receive any therapy, syncope recurred in four patients. Three of 10 patients contacted who presented with presyncope and had negative results of tilt studies reported symptoms. Conclusions: Tilt table testing is an excellent tool for diagnosing neurocardiogenic syncope in adults and in determining effective therapy in patients presenting with syncope of unknown origin.