Tilt-table testing and oral metoprolol therapy in young patients with unexplained syncope.
OBJECTIVE
Tilt-table testing is useful for investigating unexplained syncope in pediatric patients. No data are available on the use of intravenous metoprolol during testing to identify children who might respond to subsequent oral beta-adrenergic blockade or on the efficacy and safety of such oral therapy.


METHODS
To provide these data, we obtained follow-up information on 27 consecutive pediatric patients who had tilt-table testing for unexplained syncope.


RESULTS
Nineteen patients (70%) had positive test results with or without isoproterenol infusion. All these patients had negative test results after intravenous infusion of metoprolol and subsequently were treated with oral metoprolol. Taking oral metoprolol therapy alone, 9 (47%) of the 19 patients were asymptomatic, 8 (42%) reported a decreased frequency of syncopal episodes, and 2 (11%) had unchanged or more frequent episodes. The mean dosage of metoprolol required to prevent symptoms was 1.5 mg/kg per day. Mild side effects were reported by 6 (32%) of the 19 patients. Six patients (32%) required additional medications.


CONCLUSIONS
We conclude that metoprolol is safe and effective for the treatment of most cases of neurocardiogenic syncope in children and that this response cannot be predicted accurately by the use of intravenous metoprolol during testing.
O'Marcaigh
A S
AS
Section of Pediatric Cardiology, Mayo Clinic, Rochester, MN 55905.
MacLellan-Tobert
S G
SG
Porter
C J
CJ
D000284:Administration, Oral; D000293:Adolescent; D001794:Blood Pressure / Q000187:drug effects; D002648:Child; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008790:Metoprolol / Q000494:pharmacology / Q000627:therapeutic use*; D011187:Posture; D013575:Syncope / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology
D008790:Metoprolol; D007545:Isoproterenol