Estimation of the baroreflex total loop gain by the power spectral analysis of continuous arterial pressure recordings

Hiroshi Mannoji, Keita Saku, Takuya Nishikawa, Takeshi Tohyama, Kazuhiro Kamada, Kiyokazu Abe, Genya Sunagawa, Takuya Kishi, Kenji Sunagawa, Hiroyuki Tsutsui

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Baroreflex dysfunction contributes to the pathogenesis of cardiovascular diseases. The baroreflex comprises a negative feedback loop to stabilize arterial pressure (AP); its pressure-stabilizing capacity is defined as the gain (G) of the transfer function (H) of the baroreflex total loop. However, no method exists to evaluate G in a clinical setting. A feedback system with H attenuates pressure disturbance (PD) to PD/(1 + H). We hypothesized that the baroreflex attenuates the power spectrum density (PSD) of AP in the baroreflex functioning frequency range. We created graded baroreflex dysfunction in rats using a modified sinoaortic denervation (SAD) method [SAD; control (no SAD): n = 9; partial SAD (SAD in the right carotid sinus): n = 6, and total SAD (SAD in the bilateral carotid sinuses): n = 6] and evaluated the PSD of 12-h telemetric AP recordings in the light phase. Using the ratio of PSD at 0.01- 0.1 Hz (PSD slope), we normalized them with the PSD in rats with complete baroreflex failure and derived the baroreflex index (BRI), which directly reflects G. We compared BRI and G obtained from a baroreflex open-loop experiment (reference G). The PSD slope became steeper with progression of baroreflex dysfunction. BRI (control: 2.00 ± 0.31, partial SAD: 1.28 ± 0.30, and total SAD: 0.06 ± 0.10, P < 0.05) was linearly correlated with reference G (R2 = 0.91, P < 0.01). BRI accurately estimated G of the baroreflex and may serve as a novel tool for estimating the pressure-stabilizing capacity of the baroreflex in clinical settings. NEW & NOTEWORTHY This study proposed a novel method to estimate the gain of the baroreflex total loop, the so-called “baroreflex indexA. (BRI). BRI focuses on action potential variability in the frequency domain, considering baroreflex low-pass filter characteristics within 0.01- 0.1 Hz. We demonstrated that BRI was linearly correlated with the reference gain of baroreflex in rats. Thus, BRI may contribute greatly to the development of a clinical tool for estimating baroreflex pressure-stabilizing capacity.

Original languageEnglish
Pages (from-to)H828-H839
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume316
Issue number4
DOIs
Publication statusPublished - Apr 2019
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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