Beta1-Adrenoreceptor Reactivity of Human Myocardium in Ischemic Heart Disease with Preserved and Reduced Ejection Fraction of Left Ventricular and ITS Relationship with Structural and Functional Parameters of the Heart

The relationship between adrenergic reactivity of isolated myocardium of the human right atrial appendage in coronary heart disease (CHD) with preserved and reduced ejection fraction (EF) of the left ventricle (LV) upon stimulation of β1-adrenergic receptors (β1-AR) with echocardiography (EchoCG) parameters was studied. It has been shown that adrenergic reactivity, assessed by changes in the force of contractions of isolated myocardial strips in response to stimulation of β1-AR, in patients with preserved LVEF has positive dynamics at 20-minute observation. In reduced LVEF, adrenergic reactivity in response to β1-AR stimulation is weakened and does not have positive dynamics. In patients with CHD, myocardial adrenergic reactivity associated with β1-AR is a significant factor in determining intracardiac hemodynamics. This is manifested in the presence of correlations between the mechanical response of isolated myocardium upon stimulation of β1-AR and the results of echocardiography, and such correlations have different directions in patients with preserved and reduced EF. The discovered differences in the correlation of cardiac ultrasound parameters with the inotropic response of isolated myocardial fragments upon stimulation of β1-AR with preserved and reduced EF probably reflect the different severity of cardiac chamber remodeling and the state of general neurohumoral regulation in the conditions of the pathology under consideration.