N 2 (199) 2026. P. 16–21

IMPACT OF BASELINE AUTONOMIC STATUS ON SURVIVAL IN RATS WITH EPINEPHRINE-INDUCED CARDIOMYOPATHY: ANALYSIS OF HEART RATE VARIABILITY

M. O. Chyzh, I. V. Belochkina, V. Yu. Globa, I. V. Sleta

Institute for Problems of Cryobiology and Cryomedicine of the National Academy of Sciences of Ukraine, Kharkiv, Ukraine

DOI 10.32782/2226-2008-2026-2-2

Heart rate variability (HRV) reflects autonomic regulation of the cardiovascular system. Reduced HRV is associated with adverse cardiac outcomes. Excessive activation of the sympathoadrenal system by epinephrine leads to acute myocardial injury. Baseline autonomic status may have prognostic significance for survival.

Objective: to evaluate the relationship between baseline HRV parameters and survival of rats after administration of toxic doses of epinephrine.

Methods. The study included 59 white rats (12 months old). ECGs were recorded for 5 min, followed by analysis of time (SDNN, CV), geometric (HRV t.i., Mo, aMo, WAM5), and spectral (TP, VLF, LF, HF, LF/HF) indices. Epinephrine (0.5 mg/100 g) was administered subcutaneously, and animals were divided into deceased (n = 25) and surviving (n = 34) groups.

Results. Time and geometric HRV parameters showed no differences between groups (p > 0.05). In contrast, deceased rats had higher TP (225 vs. 150 ms², p = 0.02) and LF/HF (2.3 vs. 1.5; p < 0.05), indicating stronger sympathetic predominance. Surviving animals demonstrated relatively greater parasympathetic influence.

Conclusions. Time and geometric HRV indices are not reliable predictors of mortality in the epinephrine-induced cardiomyopathy model.

The LF/HF ratio serves as a valuable prognostic indicator of mortality risk in epinephrine-induced cardiopathy.

Keywords: heart rate variability, epinephrine, rats, lethality.

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