Histoenzymological characteristics of the heart conduction system: comparative study with left or right ventricle afterload.

Histoenzymological changes, indicating inhibition of the main metabolic processes, were found in the conduction cardiomyocytes of the left ventricle and ventricular septum in experimental stenosis of the aorta. The histoenzymological changes in the conduction system of both ventricles and ventricular septum were similar in experimental stenosis of the pulmonary artery and indicated primarily activation of glycolysis. The histoenzymological profile of conduction cardiomyocytes differed little in cases when the increase of the pressure load was complicated or not complicated by the development of heart failure, particularly in pulmonary artery stenosis. The histoenzymological changes in the conduction system in response to increased afterload differed significantly from those in the contractile myocardium and correlated with the level of cellular functional activity and sensitivity to the regulatory and alterative exposure. These data attest to minor role of metabolic shifts in conduction cell injuries with increasing afterload, primarily, of the right ventricle.