Timing of First Recurrence of Syncope Predicts Syncopal Frequency After Positive Tilt Table Test Result

Objectives. This study sought to determine whether the time to first recurrence of syncope after positive isoproterenol–tilt table test result accurately predicts the eventual frequency of syncope. Background. Both patient care and future clinical trials involving patients with neuromediated syncope will require simple measure that reflects the frequency of syncope. The time from tilt table testing to the first recurrence of syncope might be such measure. Methods. cohort of 46 patients with syncope, in university outpatient clinic, who had at least one syncopal spell after positive isoproterenol–tilt table test result were followed up for up to 6.5 years (mean [±SD] 48 ± 14 months). The time from tilt table testing to the first recurrence of syncope was correlated. Results. total of 40 of 46 patients had more than one recurrent spell, with median of eight recurrent spells. The time to the first syncopal spell predicted the frequency of spells with r = −0.79 (p < 0.001), whereas the time to the second spell predicted the frequency with r = −0.92 (p < 0.001). Patients who fainted within 1 month of tilt testing had geometric mean frequency of 1.35 spells/month (95% confidence limits 0.49, 3.74) compared with patients who fainted 1 to 24 months after testing (0.12 spells/month; 95% confidence limits 0.07 to 0.18, p < 0.001). Finally, the frequency of syncopal spells bore no relation to the duration of follow-up. Conclusions. The time to the first recurrent spell predicts the frequency of syncopal spells after positive tilt table test result, and the instantaneous risk of syncope is constant.