High Remission Rates in Vasovagal Syncope: Systematic Review and Meta-Analysis of Observational and Randomized...

The aims of this study were to quantify the degree of improvement in vasovagal syncope after assessment and to identify predictive factors.

No treatments for vasovagal syncope have been proved effective, but patients in all prospective studies appear to show a reduction in the likelihood of fainting.

A systematic review and meta-analysis was performed of studies published from 1993 through 2013. Inclusion criteria were: 1) vasovagal syncope frequency in the preceding 1 to 2 years; and 2) the proportion of subjects with syncope in at least the first follow-up year. Random-effects methods were used.

Of 338 screened studies, 17 were analyzed, with a mean of 112 subjects (range 9 to 511 subjects). In the preceding epoch, 97% of subjects fainted, with 2.6 ± 1.0 syncopal spells per year. In the follow-up year, the proportion of patients with ≥1 syncope recurrence was 677 of 1,912 (35.4%), and in the meta-analysis, the proportion of subjects fainting was only 0.44 (95% confidence interval: 0.41 to 0.46; p < 0.001). Subjects in larger studies were less likely to faint than those in randomized trials (relative risk: 0.35 vs. 0.55; p = 0.004). The probabilities of ≥1 syncope recurrence in the observational versus randomized studies were 0.30 (95% confidence interval: 0.24 to 0.37) and 0.54 (95% confidence interval: 0.46 to 0.62), respectively (p < 0.001). None of the degree of blinding, type of intervention, age, sex, and number of recent faints predicted the probability of syncope recurrence. Heterogeneity was very high in all analyses (I² = 60% to 96%).

The spontaneous remission rate in highly symptomatic syncope patients is high, and remission occurs in all types of studies. Improvement was more likely in larger and observational studies.