Hemodynamic effects of epinephrine in rats: evaluation by impedance cardiography

This study was aimed to examine how inotropic effects of intravenously injected epinephrine change thoracic impedance measurements and to reveal the possible effects of this change on other hemodynamic parameters by using the technique of impedance cardiography.

10 male Wistar Albino rats were divided into two equal groups: control and epinephrine. 0.2 mg/kg of epinephrine was administered to the rats in the epinephrine group via the tail vein. All hemodynamic parameters obtained by impedance cardiography [the base impedance (Z0), the maximum rate of change in impedance (dZmax/dt), the left ventricular ejection time (LVET), stroke volume (SV), cardiac output (CO), contractility index (IC), thoracic fluid content (TFC), heart rate (HR)] were recorded using the EBI 100C, DA 100 and ECG modules in the BIOPAC MP100 system.

CO (p ≤ 0.05), HR (p ≤ 0.001), dZmax/dt (p ≤ 0.05) and IC (p ≤ 0.05) increased statistically significantly in the epinephrine group compared to the control group. However, LVET (p ≤ 0.001) decreased statistically significantly in the epinephrine group compared to the control group.

Tachycardia was detected in the epinephrine group. There was an inverse correlation between LVET and dZmax/dt and IC. This is based on the fact that epinephrine increases inotropic effect (Tab. 2, Fig. 4, Ref. 30).