Abstract
Reflex syncope is a well-recognized phenomenon, but the understanding of its underlying pathophysiology remains limited. We hypothesized that patients with a history of syncope and a positive head-up tilt test (HUTT) outcome are in a “not-yet defined” abnormal state even before the head-up position. We performed a 45 min HUTT on 86 patients with a history of syncope. We assessed 19 variables during the supine period before head-up position. Of these variables, 9 were cardiovascular variables (CV) while 8 were body composition variables (BC). The two remaining variables were age and sex. Forty-five patients (41 ± 15 years, 22 males) have a positive HUTT outcome and 41 a negative one (46 ± 15 years, 22 males). Statistical tests applied on each of the 19 variables individually did not discriminate patients with a positive and a negative outcome. We used neural networks to screen the sets of variables that allowed for the best predictions of HUTT outcomes. The sensitivity, specificity, positive and negative predictive values (PPV and NPV, respectively) were determined. The best set of predictive values determined from the 19 variables was 76, 81, 78 and 80% for sensitivity, sensibility, PPV, and NPV, respectively. Unexpectedly, the HUTT outcome prediction performed with cardiovascular variables was not better than the prediction performed with body composition variables only. Patients with a positive HUTT outcome are in an abnormal state that can be detected even before the head-up position. Body composition is an important contributor to this abnormal state.
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Acknowledgement
This study was supported by a grant from Centre Evian pour l’Eau. We thank Dr Nisha Charkoudian, PhD for the critical reading of the manuscript and assistance with correct use of English.
Disclosures: The sponsor of the study had no role in the study design, data collection, data analysis, data interpretation or writing of the report.
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Fortrat, JO., Schang, D., Bellard, E. et al. Cardiovascular variables do not predict head-up tilt test outcome better than body composition. Clin Auton Res 17, 206–210 (2007). https://doi.org/10.1007/s10286-007-0423-2
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DOI: https://doi.org/10.1007/s10286-007-0423-2