Canadian Journal of Cardiology

Sex Differences in Vasovagal Syncope: A Post Hoc Analysis of the Prevention of Syncope Trials (POST) I and II

Published:October 14, 2019DOI:



      Vasovagal syncope (VVS) occurs in > 40% of individuals at least once in their lifetime. Sex-dependent differences in presentation and outcomes are not understood. We sought to determine differences in clinical presentation, treatment modalities, and outcomes of VVS between men and women.


      Data were collected as part of the Prevention of Syncope Trials (POST) I and II, 2 multicenter, placebo-controlled, randomized trials testing the effectiveness of metoprolol and fludrocortisone, respectively. Data regarding clinical presentation, outcomes, and time to first syncope event after randomization were compared.


      Of the 418 patients (280 women and 138 men), women were younger at the time of first syncope event (21 vs 26 years P = 0.002) and had a lower baseline systolic blood pressure (117 vs 124 mm Hg, P < 0.001). Response to heat as a trigger for syncope was more common in women (68% vs 48%, P = 0.011). Clinical presentation in women consisted more commonly of feeling warm, having seizures, and experiencing more postsyncope fatigue (68% vs 54%, P = 0.048; 10% vs 2.7%, P = 0.045; 75% vs 59%, P = 0.017, respectively). Women were more likely to experience recurrent syncope after adjustment for prerandomization syncope burden and randomization assignment (hazard ratio, 1.56; 95% confidence interval, 1.10-2.22; P = 0.012).


      Clinical presentation and provocative factors of VVS differ between men and women, as do recurrent events. Recognition of these differences may help target therapy specifically in men and women.



      La syncope vasovagale (SVV) survient chez > 40 % des individus au moins 1 fois au cours de leur vie. On ne comprend pas les différences sexuelles dans le tableau clinique et les résultats cliniques. Nous avons cherché à déterminer les différences dans le tableau clinique, les modalités de traitements et les résultats cliniques de la SVV entre les hommes et les femmes.


      Les données ont été recueillies dans le cadre des études POST (Prevention of Syncope Trials) I et II, 2 études multicentriques à répartition aléatoire contre placebo qui ont testé de manière respective l’efficacité du métoprolol et de la fludrocortisone. Les données concernant le tableau clinique, les résultats cliniques et le moment du premier épisode de syncope après la randomisation ont fait l’objet d’une comparaison.


      Parmi les 418 patients (280 femmes et 138 hommes), les femmes étaient plus jeunes au moment du premier épisode de syncope (21 ans vs 26 ans, P = 0,002) et avaient une pression systolique plus faible au début (117 mm Hg vs 124 mm Hg, P < 0,001). Le déclencheur le plus fréquent de la syncope chez les femmes (68 % vs 48 %, P = 0,011) était leur réponse à la chaleur. Le tableau clinique chez les femmes était le plus souvent constitué par une sensation de chaleur, des crises et une plus grande fatigue après la syncope (68 % vs 54 %, P = 0,048; 10 % vs 2,7 %, P = 0,045; 75 % vs 59 %, P = 0,017, respectivement). Les femmes étaient plus susceptibles de subir des syncopes récurrentes après l’ajustement du fardeau de syncope avant la randomisation et l’assignation aléatoire (ratio d’incidence approché, 1,56; intervalle de confiance à 95 %, 1,10-2,22; P = 0,012).


      Le tableau clinique et les facteurs déclenchants de la SVV diffèrent entre les hommes et les femmes, tout comme les épisodes récurrents. La reconnaissance de ces différences peut contribuer à la détermination du traitement indiqué chez les hommes et les femmes.
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