Analysis of head-up tilt test responses in patients suffering from syncope and high blood pressure

We studied the difference in head-up tilt test responses between patients suffering from syncope who had hypertension and those who did not. A total of 338 consecutive patients with syncope underwent head-up tilt testing in our department from January 2003 to October 2004. Of these, 243 did not have hypertension (group A), whereas 95 did (group B). There were significant differences between the groups in age (P=.0001), sex (P=.048), timing of syncope development (P=.0001), and prevalence of diabetes mellitus (P=.0001). The head-up tilt test gave positive results in 168 patients (69.1%) in group A and in 63 (66.3%) in group B (P=.6; NS). There was no significant difference between the groups in the proportion of positive responses that occurred in either the baseline or nitroglycerin-enhanced phase of the test (P=.673; NS), nor in the time to onset of syncope in either phase (P=.69; NS, and P=.28; NS, respectively). However, there was a significant difference in the type of response (vasodepressor response, 33% in group A versus 49% in group B, P=.01). In the multivariate analysis, no independent variable was found to be associated with the result of the head-up tilt test.