Cardiac autonomic innervation following coronary artery bypass grafting evaluated by high resolution heart rate variability

Objective of this preliminary study is to propose a method to assess the status of autonomic nervous regulation and adaptation reserves of the body in patients with multivessel coronary artery disease (MCAD) in the preoperative and early postoperative period after CABG. A modified Indicator of the Activity of Regulatory Systems (IARS) has been used, whose value is determined by the estimated 5 HRV indices: heart rate (HR), standard deviation of examined normal RR interval (SDNN), geometrical HRV index, low frequency (LF) and very low frequency (VLF) bands of total HRV spectrum. The results show: i. Significantly higher sympathetic tone towards the parasympathetic contour preoperative (p <;0.001) and postoperative (p <;0.0001), and this prevalence increases postoperative; ii. Parasympathetic tone is moderately suppressed preoperative and to a greater extend postoperative (p <;0.05); iii. Compared to the moderate stress of the regulatory systems preoperative (IASR = 4.07), in the early postoperative period, they are in a state of high tone (IASR = 5.36; p <;0.05), with increased activity of renin-angiotensin-aldosterone system to provide a higher adaptability of the organism.