Syncope: vasovagal: atenolol helped control symptoms.

Clinical bottom line (level 2b)

  1. Patients with vasovagal syncope who took atenolol compared with placebo were more likely to have a negative tilt-table test at one month (NNT = 2 at 4 weeks) .
  2. Patients on atenolol were more likely to report an improvement in symptoms (NNT = 2 at 4 weeks) .
Mahanonda et al: American Heart Journal 1995; 130: 1250-1253
Expires October 2004

The study

Double-blinded concealed randomised trial with intention-to-treat
Setting: acute hospital, Thailand

42 patients (aged mean 41 years, 62% female) vasovagal syncope (defined as at least one episode of syncope or two episodes of presyncope in the last month, and a positive tilt-table test.)

Excluded if
  • history of asthma or COPD, heart block, peripheral vascular disease, uncontrolled diabetes
  • bradycardia (< 50 beats/min)
  • abnormal ECG
  • structural heart disease on echocardiogram, except mitral valve prolapse
  • sensitivity to beta-blockers


    • Control Group: (n = 21, 16 analysed): placebo
    Experimental Group: (n = 21, 17 analysed): atenolol 50 to 100 mg po once daily depending on resting heart rate

    79% followed for 4 weeks

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    positive tilt-table test 4 weeks 20
    (95.2%)    		 8
    (38.1%)    		 60%
    (30% to 77%)    		 57.1%
    (34.5% to 79.8%)    		 2
    (1 to 3)
    no improvement in symptoms 4 weeks 15
    (71.4%)    		 6
    (28.6%)    		 60%
    (17% to 81%)    		 42.9%
    (15.5% to 70.2%)    		 2
    (1 to 6)

    Comments

    1. Short follow-up with significant loss to follow-up makes these results less certain.

    Citation

    1. Mahanonda N, Bhuripanyo K, Kangkagate C, et al: Randomized double-blind, placebo-controlled trial of oral atenolol in patients with unexplained syncope and positive upright tilt table test results. American Heart Journal 1995; 130: 1250-1253
    Contributor: Bob Phillips and Clare Wotton, October 2000
    Reviewer:

    Clinical Question.
    Patient vasovagal syncope
    Intervention or Exposure atenolol
    Comparison placebo
    Outcome negative tilt-table, improvement