Reproducibility of head-up tilt-table testing in pediatric patients with neurocardiogenic syncope

Usefulness of ambulatory blood pressure monitoring and head-up tilt test in the evaluation of paediatric syncope

OBJECTIVES

The aim of this study was to investigate the usefulness of ambulatory blood pressure monitoring versus head-up tilt test in the evaluation of children with a history of syncope.

STUDY DESIGN

We considered 146 consecutive children with more than one episode of syncope. All patients had a normal electrocardiogram at rest and were otherwise considered to be healthy. Forty-six patients,19 male, with a mean age of 13.6 plus or minus 5.6 years, were studied with a head-up tilt test and 100 patients, 41 male with a mean age of 9.4 plus or minus 5.6 years, were studied with ambulatory blood pressure monitoring. Twelve patients underwent both procedures. Hypotension during ambulatory blood pressure monitoring was defined when mean blood pressure values were lower than the 50th centile and the head-up tilt test was positive when syncope occurred. All patients were followed for 10 plus or minus 2 months.

RESULTS

Ambulatory blood pressure monitoring showed postural hypotension in 91% children, while head-up tilt test was positive for 54%. In the group of children having both tests, two of them were negative for both, 10 of 12 children had a positive ambulatory blood pressure monitoring while only five of 10 children had a positive response to head-up tilt test.

CONCLUSIONS

When a child with a normal resting electrocardiogram is referred with a typical history of syncope, the use of ambulatory blood pressure monitoring as a non-invasive first step for diagnosis of postural hypotension may be more sensitive than the head-up tilt test. Behavioural adjustments resolved the continued syncope in most cases. If episodes persist then the head-up tilt test is indicated.

Head-up tilt table testing in syncope: safety and efficiency of isosorbide versus isoproterenol in pediatric population

BACKGROUND

The aim of this study was to compare the diagnostic value and safety of sublingual isosorbid dinitrate (ISDN) with intravenous isoproterenol (ISOP) during head-up tilt table testing (HUTT) in pediatric patients with suspected neurocardiogenic syncope.

METHODS

One hundred thirty-six consecutive pediatric patients complaining of presyncope or syncope were submitted to HUTT for the first time. Those who did not develop syncope or presyncope during passive HUTT for 20 minutes underwent repeated HUTT with either 1.25 to 2.5 mg sublingual ISDN or intravenous ISOP (1-3 mug/min) for 20 minutes. There were 54 boys and 82 girls, aged 10 to 18 years with an average of 15.5 +/- 2.4 years and a median of 16 years. Among the patients with cardioinhibition or mixed responses, the severity of the bradyarrhythmia was scored 1 to 3 (restoration of effective rhythm within 10 seconds, 10-20 seconds, and >20 seconds while back to supine position, respectively).

RESULTS

During the passive period, 24 (17.6%) of 136 patients had a positive response to HUTT. Syncope was observed in another 44 patients during either ISDN or ISOP period (14/58 [24.1%] and 30/54 [55.5%] with ISDN vs ISOP, respectively, P < .05). The time to symptoms was shorter with both ISDN and ISOP compared with passive period (6.5 +/- 2.9, 6.3 +/- 5.9, and 10.3 +/- 4.4, minutes, respectively, P < .05). The severity score for cardioinhibition response was significantly higher with ISDN compared with the passive period and ISOP (2 +/- 0.8, 1.25 +/- 0.45, and 1.26 +/- 0.45, respectively, P < .01).

CONCLUSIONS

Sublingual ISDN is less sensitive and less safe compared to intravenous ISOP in assessing pediatric age patients with suspected neurocardiogenic syncope and with a negative result in tilt test without provocation. The simplicity of ISDN use should be weighed against the risk of longer symptoms with ISDN.