Author + information
- Received February 19, 2016
- Revision received April 29, 2016
- Accepted May 12, 2016
- Published online December 1, 2016.
- Ashish Chaddha, MD,
- Kevin E. Wenzke, MD,
- Michele Brignole, MD,
- Stephen L. Wasmund, PhD,
- Richard L. Page, MD and
- Mohamed H. Hamdan, MD, MBA∗ ()
- Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
- ↵∗Reprint requests and correspondence:
Dr. Mohamed H. Hamdan, Division of Cardiovascular Medicine, University of Wisconsin, H4/534 Clinical Science Center, 600 Highland Avenue, Madison, Wisconsin 53792-3248.
Objectives The purpose of this study was to better understand the role of the baroreflex in tilt-induced vasovagal syncope (VVS).
Background The role of the baroreflex in tilt-induced VVS remains controversial. The authors hypothesized that: 1) patients with positive tilt table test (TTT) results have greater baroreflex gain (BRG) compared with patients with negative TTT results; and 2) patients with tilt-induced asystole have greater BRG compared with patients without asystole.
Methods Using the sequence method, BRG measurements were obtained in 438 consecutive patients undergoing TTT. Two hundred sixty-eight patients (61%) had positive TTT results (mean age 50 ± 21 years; 34% men), and 170 patients (39%) had negative TTT results (mean age 48 ± 21 years; 35% men).
Results Mean BRG was significantly higher in patients with positive TTT results compared with those with negative TTT results (12.9 ± 6.0 ms/mm Hg vs. 11.5 ± 6.0 ms/mm Hg; p = 0.01). Among the 268 patients with positive TTT results, 23 (9%) had more than 3 s of asystole (mean age 37 ± 17; 30% men), and 245 patients had a mixed vasodepressor or cardioinhibitory response without asystole (mean age 51 ± 17 years; 34% men). Mean BRG was greater in patients with tilt-induced asystole (>3 s) compared with patients without asystole (15.3 ± 5.9 ms/mm Hg vs. 12.7 ± 5.9 ms/mm Hg; p = 0.03).
Conclusions The results of this study demonstrate that baseline BRG was higher in patients with positive TTT results compared with those with negative TTT results, with greater values noted in patients with tilt-induced asystole (>3 s) compared with those without asystole.
This work was supported in part by funds provided from the Mildred and Marv Conney Chair in Cardiology. The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received February 19, 2016.
- Revision received April 29, 2016.
- Accepted May 12, 2016.
- American College of Cardiology Foundation