Head-up tilt testing potentiated with sublingual nitroglycerin for the diagnosis of unexplained syncope in children / 中华儿科杂志

ABSTRACT

<p><b>OBJECTIVE</b>Syncope is one of the common problems in clinical pediatrics. In recent years, vasovagal reflex was identified as the most common reason for unexplained syncope. Head-up tilt test (HUT) was regarded as one of the important diagnostic criteria. But the sensitivity of baseline head-up tilt test (BHUT) is low. To improve the sensitivity of HUT, we evaluated the diagnostic value of head-up tilt testing potentiated with sublingual nitroglycerin (SNHUT) in children with unexplained syncope.</p><p><b>METHODS</b>Twenty-five patients (11 male and 14 female, mean age 11.8 +/- 2.1 years, ranged from 8 to 15) with unexplained syncope and 10 healthy children in control group (5 male and 5 female, mean age 11.4 +/- 2.1 years, ranged from 9 to 15) were studied. The patients and healthy children were tilted upright to 60 degrees for 45 minutes at BHUT. If syncope did not occur, sublingual nitroglycerin (4 - 6 microg/kg, maximum dose 300 microg) was administered, and continued at same degree for 20 minutes.</p><p><b>RESULTS</b>Compared with controls, there was no significant difference in sex, age, supine blood pressure and supine heart rate of syncopal group (P > 0.05). During BHUT, 12 patients (48%) and none of the controls had positive response, whereas another 8 patients and 2 controls had positive response during SNHUT. In syncopal group, total positive rate was 80%. The sensitivity, specificity, and diagnostic value of SNHUT were all 80%. During SNHUT, the mean time to positive response was 5.9 +/- 2.9 minutes (from 4 to 11 minutes), and only 1 patient had mild headache.</p><p><b>CONCLUSION</b>Head - up tilt testing potentiated with sublingual nitroglycerin (4 - 6 microg/kg, maximum dose 300 microg) as pharmacological provocation test was a useful and an objective diagnostic tool for evaluating vasovagal syncope in children.</p>