Author + information
- Received July 23, 1990
- Revision received October 24, 1990
- Accepted November 9, 1990
- Published online April 1, 1991.
- James C. Perry, MD∗ and
- Arthur Garson Jr., MD, FACC
- ↵∗Address for reprints: James C. Perry, MD, Pediatric Cardiology, 6621 Farmin, Houston, Texas 77030.
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 < 0.01) and lower norepinephrine level in the upright position (628 ± 219 versus 891 ± 270 pg/ml, p < 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 < 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 alter 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.
- Received July 23, 1990.
- Revision received October 24, 1990.
- Accepted November 9, 1990.