Effect of beta-adrenergic stimulation on the QT interval of children with syncope

Seshadri Balaji, P. C. Oslizlok, C. A. McKay, M. C. Allen, C. L. Case, K. W. Hewett, P. C. Gillette

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4 Scopus citations


The effect of intravenous bolus doses (0.25, 0.5, 1.0 μg) of isoproterenol on the QT and RR intervals was reviewed in a group of 34 children undergoing autonomic testing for syncope. Twenty-one patients had a positive orthostatic test and 13 were negative. The two groups (positive and negative) were compared. Baseline QT and RR intervals were similar. The RR interval was shortened by isoproterenol in both groups. Isoproterenol shortened the QT interval in the negative group (as seen in normal persons), but produced QT prolongation in the positive group, although neither reached statistical significance when compared to baseline within the respective group. Comparing the values for RR and QT at each dose of isoproterenol (including baseline) between the two groups showed a significant difference in the QT interval after the 1.0-μg dose of isoproterenol. Thus children with orthostatic positive neurocardiogenic syncope showed a different QT response to β-adrenergic stimulation. This lends support to the theory of altered β-adrenergic sensitivity being present in children with neurocardiogenic syncope.

Original languageEnglish (US)
Pages (from-to)152-156
Number of pages5
JournalPACE - Pacing and Clinical Electrophysiology
Issue number2
Publication statusPublished - 1994
Externally publishedYes


ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

Balaji, S., Oslizlok, P. C., McKay, C. A., Allen, M. C., Case, C. L., Hewett, K. W., & Gillette, P. C. (1994). Effect of beta-adrenergic stimulation on the QT interval of children with syncope. PACE - Pacing and Clinical Electrophysiology, 17(2), 152-156.