Lack of efficacy of atenolol for the prevention of neurally mediated syncope in a highly symptomatic population: a prospective, double-blind, randomized and placebo-controlled study.
OBJECTIVE
This study was designed to evaluate the efficacy of atenolol for the long-term management of patients with vasovagal syncope. The primary hypothesis was that atenolol is not superior to placebo for the treatment of vasovagal syncope.


BACKGROUND
There is no definitive well-controlled analysis of the efficacy of beta-adrenergic blocking agents in patients with recurrent vasovagal syncope.


METHODS
This is a prospective, randomized, double-blind, placebo-controlled study. Fifty patients with recurrent vasovagal syncope were included (at least two episodes in the last year). A baseline tilt test was performed. Twenty patients (40%) had a positive tilt test. Intravenous atenolol prevented a second positive tilt in five patients. The patients were randomized to receive either atenolol or a placebo (26 patients atenolol 50 mg/day, 24 patients placebo). The follow-up procedure lasted one year. The primary end point of the study was the time to first recurrence of syncope.


RESULTS
In the intention-to-treat analysis, the group treated with atenolol had a similar number of patients with recurrent syncopal episodes as the placebo group. The Kaplan-Meier actuarial estimates of time to first syncopal recurrence showed that the probability of remaining free of syncope drops similarly in both groups and that there was no statistical difference between both curves (patients treated with atenolol vs. the placebo) with a log-rank test p value of 0.4517.


CONCLUSIONS
The recurrence of neurocardiogenic syncope in highly symptomatic patients treated with atenolol is similar to that of patients treated with placebo.
Madrid
A H
AH
Cardiology Department, Ramón y Cajal Hospital, Alcalá University, Madrid, Spain.
Ortega
J
J
Rebollo
J G
JG
Manzano
J G
JG
Segovia
J G
JG
Sánchez
A
A
Peña
G
G
Moro
C
C
D000293:Adolescent; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage*; D000328:Adult; D000368:Aged; D001262:Atenolol / Q000008:administration & dosage* / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012008:Recurrence; D019462:Syncope, Vasovagal / Q000209:etiology / Q000517:prevention & control*; D018667:Tilt-Table Test; D017211:Treatment Failure
D000319:Adrenergic beta-Antagonists; D001262:Atenolol