Prospective evaluation of day-to-day reproducibility of upright tilt-table testing in unexplained syncope.
To evaluate the day-to-day reproducibility of upright tilt-table testing, 109 patients with unexplained syncope prospectively underwent testing on 2 consecutive days using a uniform protocol. Results of testing on 2 separate days were concordant in 69 of 109 patients (63%), and discordant in 40 of 109 patients (37%). Thirty-six of 109 patients (33%) had vasodepressor syncope on 1 or both days of testing. Nineteen of 30 patients (63%) with vasodepressor responses on the first day did not reproduce this response during the second day of testing. An additional 6 patients with an initial negative tilt test had a vasodepressor response on the second day. Only 11 of 36 patients (31%) had reproducible vasodepressor responses on both days of testing. Patients with reproducible vasodepressor responses had a significantly higher mean number of preceding clinical syncopal events than patients with 2 normal tests (p < 0.02) or nonreproducible results (p < 0.04). In addition, these patients had a significantly longer duration of clinical symptoms relative to patients with 2 tests that yielded negative results (p < 0.008) and nonreproducible results (p < 0.01). The elapsed time between the most recent clinical event and the performance of tilt-table testing was not significantly different among the 3 groups, and did not appear to influence the outcome of testing. These data show that vasodepressor responses elicited by upright tilt-table testing show day-to-day variability in many patients, a finding that may limit the interpretation of initial and follow-up test results.
Brooks
R
R
Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston 02114.
Ruskin
J N
JN
Powell
A C
AC
Newell
J
J
Garan
H
H
McGovern
B A
BA
D000328:Adult; D000368:Aged; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007024:Hypotension, Orthostatic / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011187:Posture; D011446:Prospective Studies; D015203:Reproducibility of Results; D013575:Syncope / Q000209:etiology / Q000503:physiopathology*; D014666:Vasomotor System / Q000503:physiopathology*