Nitrate-stimulated tilt testing enhances the predictive value of the tilt test on the risk of recurrence in patients with suspected vasovagal syncope.

Objective: Nitrate-stimulated tilt testing may be used to diagnose vasovagal syncope and to guide therapy. However, to date the predictive value of the test is undetermined. This study analyses the risk of recurrence of syncope in vasovagal patients on the basis of a nitrate-stimulated tilt result and other clinical factors.

Methods And Results: We used a combined passive and nitrate-stimulated tilt protocol. One year after the test a questionnaire, asking about recurrence of syncope and other demographic factors, was sent to 131 patients. Passive tilting was found not to be a useful predictor; recurrence rates after a positive and negative test were 26% and 30%, respectively, and non-significant. With the addition of sublingual nitrates the test became a significant predictor; recurrence rates were 34 (34%) with a positive and 4 (13%) with a negative tilt test (p = 0.031). Univariate analysis of the clinical factors revealed that gender and pre-test symptomatology were significant predictors of recurrence. Multivariate analysis revealed no additional relationships.

Conclusion: In patients with suspected vasovagal syncope, a positive tilt test with sublingual nitrates together with the clinical factors gender and symptomatology, are predictors for recurrence of syncope during one year of follow-up. Without specific therapy the prognosis of vasovagal syncope is good.