Effect of beta blockers on the time to first syncope recurrence in patients after a positive isoproterenol tilt table test

Isoproterenol-headup tilt table testing provides a diagnosis of neuromediated syncope in many patients who faint. The involvement of β-adrenoceptor stimulation in the provocation of syncope suggests that β blockers might chronically prevent syncope. To assess this, a cohort of 153 syncope patients (age 39 ± 20 years) underwent baseline assessment of demographic variables, symptomatic burden, and hemodynamic and clinical responses to tilt testing. Fifty-two patients then received β blockers, and 101 did not receive drug therapy. The primary outcome was the time to the first recurrent syncopal spell. Actuarial survival analysis was used. Syncope recurred in 17 of 52 patients who received β blockers and in 28 of 101 patients who were untreated. The actuarial probability of remaining free of syncope was similar in both groups. For example, the probability of remaining free of syncope 12 months following the tilt test was 0.72 in both populations. Thus, treatment with β blockers may not have a significant effect in preventing syncope recurrence following a positive tilt test.