Symbolic analysis of heart rate fluctuations identifies cardiac autonomic modifications during LPS-induced endotoxemia

• Published in: Autonomic neuroscience Vol. 221; p. 102577
• Main Authors: Reyes-Lagos, José Javier, Ledesma-Ramírez, Claudia Ivette, Hadamitzky, Martin, Peña-Castillo, Miguel Ángel, Echeverría, Juan C., Lückemann, Laura, Schedlowski, Manfred, Berg, Karsten, Wessel, Niels, Pacheco-López, Gustavo
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-11-2019
• Subjects: Animals; Autonomic function; Endotoxemia; Endotoxemia - chemically induced; Endotoxemia - physiopathology; Heart Conduction System - physiopathology; Heart Rate - physiology; HRV; Lipopolysaccharides - toxicity; LPS; Male; Nonlinear Dynamics; Rats; Rats, Inbred Strains; Symbolic dynamics; Vagus Nerve - physiopathology; Symbolic dynamics; Autonomic function; HRV; Endotoxemia; LPS
• ISSN: 1566-0702; 1872-7484
• DOI: 10.1016/j.autneu.2019.102577

The present study aimed to compare linear and symbolic dynamics (SD) indices for detecting the autonomic cardiac changes produced by endotoxemia in freely-moving rats. In this context, we analyzed ECG-derived R-R time series in freely moving Dark Agouti rats, which received lipopolysaccharide (LPS, n = 9), or vehicle (V, n = 7). Five minutes R-R time series were assessed every hour up to +12 h and + 24 h post-LPS injection.
We found that SD indices showed significant differences at +7 h between V vs. LPS groups and at +9 h between basal levels of LPS (−3 h) and post-LPS injection (pre-LPS vs. post-LPS). In general, SD seems more appropriate than linear indices to evaluate the autonomic changes of endotoxemic rats. Overall, the symbolic parameters detected decreased R-R variability and complexity, which indicate a modification of the autonomic regulation during LPS-induced endotoxemia. This modification is probably related to a reduced activity of the cholinergic anti-inflammatory pathway at the long term.