The purpose of this study to evaluate the effectiveness of metoprolol versus conventional treatment in the prevention of syncope recurrence in children and adolescents.

Syncope is often a frustrating clinical problem seen in pediatric patients. Most pediatric syncope is benign, and vasovagal syncope (VVS) is the most common type of syncope seen in children . The diagnosis of VVS is established by history, often confirmed by tilt tests. A wide range of drugs has been proposed for VVS , with β-adrenergic blocking agents being first-line therapy. However, clinical studies have shown conflicting results in terms of therapy effectiveness. β-blockers have been claimed to be effective for 60% to 100% of young patients in many uncontrolled studies but not in most short- and long-term controlled studies . Sheldon et al., in a recent multicenter, double-blinded, placebo-controlled, randomized study of adult patients, reported that metoprolol was not effective in preventing VVS. To our knowledge, no pediatric randomized controlled trials with long-term follow-up have demonstrated the efficacy of β-blockers for the prevention of syncope.

Inclusion Criteria:

• Children with a history of syncope were included if they had had at least three syncopal episodes per year and had a positive head-up tilt test result.

Exclusion Criteria:

• Patients were excluded if they had:

  • Other causes of syncope;
  • Cardiovascular and/or systemic disease;
  • Systolic blood pressure >130 mm Hg or diastolic blood pressure >90 mm Hg； or
  • History of asthma, impaired liver function, Ⅱ to Ⅲ degrees of atrioventricular block, sinus bradycardia < 40 beats/min, or other contraindications for β-blockers.