Correlation between Head-Up Tilt Test and Spontaneous Baroreflex Sensitivity in a Supine Position on the Diagnosis of Orthostatic Hypotension

Ha, Eunok; Kim, Young-Soo; Park, Ki-Jong; Kim, Soo-Kyoung; Kang, Heeyoung; Choi, Nack-Cheon; Kwon, Oh-Young; Lim, Byeong-Hoon; Yoo, Nam Tae

Ann Clin Neurophysiol > 2010 ;12(2) > Article

Ann Clin Neurophysiol. 2010; 12(2): 61-65.

Eunok Ha, Young-Soo Kim, Ki-Jong Park, Soo-Kyoung Kim, Heeyoung Kang, Nack-Cheon Choi, Oh-Young Kwon, Byeong-Hoon Lim, and Nam Tae Yoo

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

ABSTRACT

Background: Orthostatic hypotension (OH) refers to a fall in systolic blood pressure (BP) of 20 mmHg or more, or indiastolic BP of 10 mm Hg or more within 3 minutes of standing up. The head-up tilt test (HUT) is the most useful, butpotentially invasive test for the diagnosis of OH. The purpose of this study was to identify the usefulness of spontaneousbaroreflex sensitivity (sBRS).
Methods: Ninety one patients with orthostatic intolerance, in whom the HUT data were available,were included in the study. Patients were classified into HUT-positive (group I) and HUT-negative (group II) group.Twenty five healthy volunteers served as normal controls, and were designated as group III. In all subjects, beat-to-beat BPand heart rate were recorded using BeatScope 1.1a. We collected the 50 sBRS data in each patient in a supine position.The average value of one to ten of 50 sBRS data was defined as sBRS10, one to twenty as sBRS20, one to thirty as sBRS30, one to forty as sBRS 40, and one to fifty as sBRS 50. Differences in sBRS10 and sBRS50 levels were statisticallyanalyzed and compared between groups I, II, and III.
Results: No significant difference in the sBRS50 level was found betweenGroups II and III. sBRS50 was significantly lower in Group I than in Groups II and III (p<0.05), and the same patternof differences was observed for sBRS40, sBRS30, sBRS20, and sBRS10.
Conclusions: Patients with OH showed significantlylower sBRS levels than HUT-negative patients or normal controls. Our study implies that a supine-position sBRS would provideadditional diagnostic information for OH.

Key words: Orthostatic hypotension, Head-up tilt test, Spontaneous baroreflex sensitivity