3. Vasovagal Syncope, Tilt Testing

Objective To evaluate the sensitivity and specificity and to establish the positive and negative predictive values for the tilt test in patients with syncope of unknown origin. Methods We studied patients with history of dizziness or syncope without any underlying cardiac condition (group A), and another group consisting of healthy volunteers that did not have history of dizziness or syncope (group B). They were initially tilted upright to 70° during 30 min. If the result was negative, 5 mg of sublingual isosorbide dinitrate were given and the patients were tilted upright to 70° again. Results Of the last 156, a total of 134 patients (45 males and 89 females, mean age of 27.9±14 yrs) had had syncope (Group A), whereas 22 were normal subjects (7 male and 15 females, mean age of 25.4±6.4) that volunteered for the same test. During the panic phase of tilt test syncope occurred in 25 patients (18.7%) of group A, and 5 (22.7%) of group B. 109 were submitted to the drug phase: (81.3%) of group A, and 17 (72.3%) of group B. Sixty patients of group A (55%), and 8 of group B (47%) had a positive test. This increased sensitivity from 18 to 55% and decreased specificity from 77 to 52%. The positive rate of tilt test was 62.8%, the sensitivity 63% and the specificity 40%; the positive predictive value was 0.86, and the negative predictive value 0.15. Conclusions We consider that either the tilt test is not the ideal to evaluate vaso-vagal syncope, or this is only a physiological condition related to other factors such as anxiety.