CIRCULATORY RESPONSES IN CHILDREN WITH UNEXPLAINED SYNCOPE EVALUATED BY CONTINUOUS NONINVASIVE FINGER BLOOD-PRESSURE MONITORING

Cardiovascular responses on active standing in children with unexplain ed syncope were investigated with continuous non-invasive finger arter y pressure monitoring (Finapres). We examined 34 symptomatic patients (13 boys and 21 girls), aged 8-16 years, and 24 age-matched controls. Finger blood pressure and heart rate were monitored continuously for 5 min in the supine position and for 10 min while standing. Ten of 34 p atients developed fainting symptoms with hypotension during upright po sture (fainters). In the initial standing phase (0-30 s), two prominen t abnormal blood pressure responses were found in patients: a marked d ecrease 45 +/- 18/23 +/- 8 mmHg and a prolonged recovery time (16.5 +/ - 2.9 versus 27.7 +/- 13.6 s), which appeared to be based on impaired vasoconstriction. Either or both abnormalities were observed in 21 (62 %) of the 34 patients and in 2 (8%) of the controls. In addition, fain ters also had a more marked increase in heart rate during standing com pared with non-fainters. Our findings suggested that more than half of children with syncope had abnormal cardiovascular reflexes in the ini tial phase which appeared to be associated with vasodepressor syncope. The active standing test with a continuous beat-to-beat blood pressur e recording has a high sensitivity in detecting abnormalities of auton omic function in patients with unexplained syncope.