Bromide 1-(β-phenylethyl)-4-amino-1,2,4-triazolium (Hypertril) exhibits both beta-blocking and nitric oxide–mimetic activities and belongs to toxicity class IV. These pharmacological features make Hypertril a promising therapeutic agent for cardiovascular disorders. The present study aimed to evaluate the cardioprotective properties of Hypertril by assessing its impact on the morpho-functional characteristics of the myocardium in a rat model of chronic heart failure (CHF). Experimental CHF was induced in 80 white outbred rats (190–220 g) through cumulative administration of doxorubicin at a total dose of 15 mg/kg. Following CHF induction, Hypertril and the reference drug metoprolol succinate were administered orally for 30 days at doses of 3.5 mg/kg and 15 mg/kg, respectively. Morphometric evaluation of myocardial cellular architecture was performed using an Axioskop microscope (Zeiss, Germany) in automated mode, employing a macro program developed in the VIDAS-2.5 software environment (Kontron Elektronik, Germany). Treatment with Hypertril in CHF-affected rats resulted in elevated cardiomyocyte nuclear density, enlarged nuclear area, an increased nuclear-to-cytoplasmic ratio, and higher RNA content in both nuclei and cytoplasm compared to untreated controls, suggesting a strong cardioprotective activity of the compound. Moreover, Hypertril demonstrated significantly greater effects (p < 0.05) than metoprolol with respect to cardiomyocyte survival density, RNA content, and nuclear-cytoplasmic ratio.
