P108 - BETA-BLOCKERS IN THE PREVENTION OF VASOVAGAL SYNCOPE IN AGING SUBJECTS: A RANDOMIZED CONTROLLED TRIAL AND AN INDIVIDUAL PATIENT DATA META-ANALYSIS OF RCTS

Background: Previous studies suggested no benefit of beta-blockers in preventing vasovagal syncope (VVS), but a trend towards benefit was observed in older adults in post-hoc analyses, leading to North American guidelines accepting beta-blockers as a reasonable option in patients ≥42 years of age with recurrent VVS (Class IIb). In the POST-5 trial, we conducted a randomized clinical trial of metoprolol in the prevention of VVS in patients ≥40 years of age.

METHODS AND RESULTS: Patients with age ≥40 years with ≥1 syncopal spell in the prior year and ≥ -2 points on the Calgary Syncope Symptom Score were enrolled and randomized to receive either metoprolol (starting dose of 50 mg BID) or matching placebo for 12 months. POST-5 trial terminated prematurely due to investigator fatigue and insufficient funds. Additionally, an individual patient level data meta-analysis of patients with age ≥40 years was done for RCTs studying the effect of beta-blockers in VVS.
Fifty-two patients (Age 64 ± 11, 60% females) were included in POST-5 with 26 patients in each arm. Treatment arms were balanced in terms of demographic and clinical characteristics. Eight patients (31%) in the metoprolol arm and 10 patients (39%) in the placebo arm experienced syncope during median follow-up period of 12 month (p=0.69).
Five RCTs were identified in the literature. Patient-level data for patients with age ≥40 years were obtained for 3 of these trials, and were combined with the POST-5 RCT data, resulting in a total cohort of 174 patients. In the pooled cohort, 29 out of the 85 patients in the beta-blocker arms (34%) and 30 out of 88 patients (34%) in the placebo arms had recurrence of syncope (OR 0.99, 95%CI 0.43, 2.29) (Figure).

Conclusion: Beta-blockers showed no effect on reducing syncope recurrence in patients with VVS. The results of current meta-analysis may inform practice guidelines by removing their recommendations for using beta-blockers in this specific context.