Prevention of Syncope Trial (POST): a randomized, placebo-controlled study of metoprolol in the prevention of vasovagal syncope.
BACKGROUND
Previous studies that assessed the effects of beta-blockers in preventing vasovagal syncope provided mixed results. Our goal was to determine whether treatment with metoprolol reduces the risk of syncope in patients with vasovagal syncope.


RESULTS
The multicenter Prevention of Syncope Trial (POST) was a randomized, placebo-controlled, double-blind, trial designed to assess the effects of metoprolol in vasovagal syncope over a 1-year treatment period. Two prespecified analyses included the relationships of age and initial tilt-test results to any benefit from metoprolol. All patients had >2 syncopal spells and a positive tilt test. Randomization was stratified according to ages <42 and > or =42 years. Patients received either metoprolol or matching placebo at highest-tolerated doses from 25 to 200 mg daily. The main outcome measure was the first recurrence of syncope. A total of 208 patients (mean age 42+/-18 years) with a median of 9 syncopal spells over a median of 11 years were randomized, 108 to receive metoprolol and 100 to the placebo group. There were 75 patients with > or =1 recurrence of syncope. The likelihood of recurrent syncope was not significantly different between groups. Neither the age of the patient nor the need for isoproterenol to produce a positive tilt test predicted subsequent significant benefit from metoprolol.


CONCLUSIONS
Metoprolol was not effective in preventing vasovagal syncope in the study population.
Sheldon
Robert
R
University of Calgary, Calgary, Alberta T2N 4N1, Canada. sheldon@ucalgary.ca
Connolly
Stuart
S
Rose
Sarah
S
Klingenheben
Thomas
T
Krahn
Andrew
A
Morillo
Carlos
C
Talajic
Mario
M
Ku
Teresa
T
Fouad-Tarazi
Fetnat
F
Ritchie
Debbie
D
Koshman
Mary-Lou
ML
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D000367:Age Factors; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D020714:Maximum Tolerated Dose; D008790:Metoprolol / Q000008:administration & dosage*; D008875:Middle Aged; D010919:Placebos; D012008:Recurrence; D019462:Syncope, Vasovagal / Q000188:drug therapy / Q000517:prevention & control*; D018667:Tilt-Table Test; D017211:Treatment Failure
D000319:Adrenergic beta-Antagonists; D010919:Placebos; D008790:Metoprolol