Fluoxetine vs. placebo for the treatment of recurrent vasovagal syncope with anxiety sensitivity

AIMS: The optimal medical therapy of patients with vasovagal syncope (VVS) remains controversial. Fluoxetine is effective against anxiety and panic disorders, while its use has shown promising results for VVS. Anxiety sensitivity is a personality trait observed in a considerable proportion of patients with VVS, associated with predisposition to anxiety and panic disorders. Our aim was to examine whether fluoxetine exerts beneficial effects regarding VVS prevention in the subset of patients with anxiety sensitivity. METHODS AND RESULTS: We assessed 106 patients with typical history of recurrent VVS, without other comorbidities, and a diagnostic, positive head-up tilt test. A psychiatric examination ruled out clinical psychiatric disease. Their psychological, stress-related profile was assessed by the Anxiety Sensitivity Index (ASI) questionnaire, a 16-item questionnaire, assessing fear of anxiety-related sensations, previously studied in VVS. Patients scoring positive for ASI (n = 60, 57% of the population) were randomized in a 2:1 fashion to receive either 10-40 mg fluoxetine daily (n = 40) or placebo (n = 20), and were followed-up for 1 year. A significant difference was observed between patients receiving fluoxetine and those with placebo, regarding the distribution of syncope-free time during the study (P < 0.05). A significant difference was also observed between the two groups regarding presyncopal events and the total number of patients who experienced syncope or presyncope during follow-up. CONCLUSION: Sensitivity to anxiety is a common personality trait in recurrent VVS. Fluoxetine is superior to placebo against syncope in these patients. This drug may be a first-line pharmacological treatment for this difficult-to-treat group.