The child with recurrent syncope: autonomic function testing and beta-adrenergic hypersensitivity

J Am Coll Cardiol. 1991 Apr;17(5):1168-71. doi: 10.1016/0735-1097(91)90849-5.


Recurrent syncope in the child with a normal heart poses both diagnostic and therapeutic problems. To assess autonomic contributions to syncope, formal autonomic function testing was performed in 22 children (aged 7 to 18 years) with recurrent syncope and a normal heart. Autonomic testing consisted of eight to nine separate tests; 14 of the 22 patients had reproduction of syncope or symptoms during testing. Patients with a positive test had a lower norepinephrine level while supine (334 +/- 86 versus 547 +/- 169 pg/ml, p less than 0.01) and lower norepinephrine level in the upright position (628 +/- 219 versus 891 +/- 270 pg/ml, p less than 0.05) than did patients with a negative test. The slope of heart rate response versus log isoproterenol dose was greater in patients with a positive test than in those with a negative test (1.70 +/- 0.70 versus 0.89 +/- 0.19, p less than 0.01). All five patients with a positive test who were given intravenous propranolol had elimination of syncope with repeat testing. Eight of 10 patients with a positive test were successfully treated with atenolol, including 2 patients without prior resolution of symptoms after pacemaker implantation for symptoms attributed to bradycardia. Beta-adrenergic hypersensitivity may cause recurrent syncope in young patients. Inappropriate heart rate response to standing may elicit the Bezold-Jarisch reflex, resulting in bradycardia or hypotension, or both, in some patients. Beta-adrenergic blockade is of benefit in many of these patients.

MeSH terms

  • Adolescent
  • Adrenergic beta-Antagonists / therapeutic use
  • Atenolol / therapeutic use
  • Autonomic Nervous System / physiopathology*
  • Child
  • Epinephrine / blood
  • Female
  • Follow-Up Studies
  • Humans
  • Isoproterenol
  • Male
  • Norepinephrine / blood
  • Posture
  • Propranolol / therapeutic use
  • Receptors, Adrenergic, beta / physiology*
  • Recurrence
  • Syncope / blood
  • Syncope / drug therapy
  • Syncope / etiology
  • Syncope / physiopathology*


  • Adrenergic beta-Antagonists
  • Receptors, Adrenergic, beta
  • Atenolol
  • Propranolol
  • Isoproterenol
  • Norepinephrine
  • Epinephrine