Beta-Blockers for Vasovagal Syncope in Aging Subjects: A Randomized Controlled Trial and Individual Patient Data Meta-Analysis of Clinical Trials.

BACKGROUND: Previous studies provided conflicting evidence of benefit of beta-blockers (BBs) in preventing vasovagal syncope (VVS), with possible benefit in older adults, leading to North American guidelines accepting BBs as a reasonable but weak option in patients aged ≥ 42 years with VVS (class IIb). In the Prevention of Vasovagal Syncope Trial 5 (POST 5), we conducted a randomized clinical trial of metoprolol in the prevention of VVS in patients aged ≥ 40 years. METHODS: Patients aged ≥ 40 years with ≥ 1 syncopal spell in the prior year and ≥ -2 points for the Calgary Syncope Symptom Score were randomized to receive either metoprolol or matching placebo for 12 months. Patient-level meta-analysis of patients with age ≥ 40 years was done for randomized controlled trials (RCTs) studying the effect of BBs in VVS. RESULTS: A total of 51 patients (age 64 ± 11 years, 59% female) were included in POST 5 (26 metoprolol, 25 placebo). Treatment arms were balanced in demographic and clinical characteristics. Eight patients (31%) in the metoprolol arm and 10 (40%) in the placebo arm experienced syncope during a median follow-up period of 12 months (P = 0.69). In the pooled analysis of 173 patients from 4 RCTs, 29 of 85 patients on BB (34%) and 30 of 88 patients (34%) on placebo had at least one syncope recurrence (odds ratio 0.99, 95% confidence interval 0.43, 2.29). CONCLUSION: BBs showed no effect on reducing syncope recurrence in older patients with VVS. These results may inform practice guidelines by removing their recommendations for using BBs in this specific context. CLINICAL TRIAL REGISTRATION: NCT02123056.