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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.