IMMEDIATE REPRODUCIBILITY OF THE TILT-TABLE TEST IN ADULTS WITH UNEXPLAINED SYNCOPE

There are few data regarding the immediate reproducibility of the tilt-table test (TTT). Therefore, the immediate reproducibility of the TTT was examined in 19 patients (11 men and 8 women; mean age 49 +/- 19 years) with syncope or presyncope. The mean number of episodes that patients had experienced was 14 +/- 25 (range 1 to 100). After baseline supine observation for 10 minutes, patients were placed in 80-degrees of head-up tilt until a positive response occurred or for a maximum of 10 minutes. Patients were then returned to the supine position for 5 minutes, followed by retilt for another 10 minutes. If the baseline tilt was negative, the study was repeated with intravenous isoproterenol, and immediate reproducibility was examined in the same manner. The 19 patients underwent a total of 31 TTTs (19 baseline and 12 follow-up on drug). The M was immediately reproducible in 24 of 31 tests performed (77%). Eight tests were reproducibly positive and 16 negative. The results of 7 Ms (23%) (5 baseline and 2 follow-up on drug) were not reproducible. In 6 of these studies (86%), the positive result occurred first and the negative result second. The reproducibility of an initially negative M result (16 of 17; 94%) was much higher than that of an initially positive one (8 of 14; 57%). The immediate reproducibility of the M in adult patients with unexplained syncope is approximately 75%. In studies that are not reproducible, most (86%) are positive first and negative second. Therefore, in most patients it is not necessary to check immediate reproducibility. If a baseline TTT is negative, it may be reasonable to repeat the test during the same session in some patients, because in 1 of 9 cases (11%) a positive result will be found on the second test. The performance of acute drug testing is limited by the relatively poor immediate reproducibility of positive TTT results.