Introduction: Guideline states that head-up tilt (HUT) test is used as an aid in establishing the diagnosis of neurocardiogenic syncope, but serious questions about the sensitivity, specificity, and diagnostic yield of the test exist. We tested the sensitivity and specificity of HUT test in patients with unexplained syncope or presyncope.
Methods: From Mar 2011 to August 2011, consecutive 117 patients (75 men and 42 women, mean age 45±18 years) who underwent HUT test were reviewed. All the patients underwent the first phase of HUT using 70° of tilting for 30 minutes, or until symptoms appeared. If the first phase of HUT was negative, the second phase of HUT was performed with low-dose isoproterenol infusion.
Results: Among 117 patients, 36 (30.8%) showed syncope at 12±8 min after the initiation. Among 36 patients with syncope, 21 patients showed syncope in the second phase of HUT. Twenty-four patients were diagnosed with other disorders such as epilepsy (25%), malignancy (21%), arrhythmia (17%), or benign paroxysmal positional vertigo (13%). The sensitivity and specificity of overall HUT test were 33.3% and 79.2%, respectively (Table 1). The sensitivity and specificity of HUT test without low-dose isoproterenol infusion were 14.0% and 91.7%.
Conclusion: Although low-dose isoproterenol infusion was useful to increase sensitivity, HUT test sensitivity was low and specificity was not high in our real-world practice, indicating that it is rarely needed to make the diagnosis.
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