Impact of extract of cryopreserved pig heart fragments in alginate hydrogel on electrophysiological indicators of rat hearts with myocardial cryonecrosis
Authors: Belochkina I.V. , Chyzh M.O. , Sleta I.V. , Skand T.V. 
Published: November 2024

Background. The issue of stimulating reparative myocardial regeneration in ischemic heart disease (IHD) is a pressing one, requiring in-depth experimental and clinical research. Consequently, considerable attention is currently being paid to studies on the effectiveness and mechanisms of action of regenerative plastic therapy for pathological conditions of the cardiovascular system. To prevent cardiac aneurysms in the early post-infarction period and to treat progressive chronic heart failure, biodegradable polymer hydrogels, including alginate polysaccharide hydrogels, are used as surgical implants.

Purpose – analysis of electrophysiological indicators of the heart during the development of necrosis and organ remodeling in a myocardial cryodestruction model and the introduction of an alginate implant saturated with an extract of cryopreserved pig heart fragments to determine the cardioprotective effect of these factors.

Materials and Methods. Electrocardiograms (ECGs) were recorded in three standard leads (I, II, III) and three additional leads (aVR, aVL, aVF) using the «PolySpectrum/8V» hardware-software complex («Poly-Spectrum», Ukraine). The «PolySpectrum-Analysis» software allows for contour analysis of the averaged cardiocomplex. Initially, we conducted an experiment to assess the impact of sodium alginate hydrogel alone on electrocardiographic parameters without heart cryoinjury. Subsequently, the experimental animals were divided into three groups: 1 – control group, animals with myocardial necrosis (MN) without treatment; 2 – rats with MN and an implant (sodium alginate hydrogel) introduced into the cryonecrosis area; 3 – rats with MN and an alginate implant saturated with cryopreserved pig heart extract (CPHE) introduced into the cryonecrosis area. The normal group consisted of 7 rats.

Results. The use of an extract from cryopreserved heart fragments of piglets, delivered via an alginate carrier, in the context of myocardial infarction induced by local cryodestruction of the heart, significantly accelerates the recovery of the left ventricular myocardium compared to both the control group and the experimental groups receiving alginate hydrogel alone. This is supported by electrocardiographic evidence: a positive P wave on the first day indicates the preservation of the myocardial excitation source at the sinoatrial node level; recovery of the R wave to normal levels by the seventh day reflects the restoration of myocardial contractile function; and on the 30th day, the group treated with the ECP in alginate gel shows a QRS complex shape that conforms to normal standards, with minimal cardiac remodeling as evidenced by the absence of a Q wave in the ECG. In contrast, up to 40% of animals in other groups exhibit signs of transmural myocardial necrosis, indicated by the persistent presence of the Q wave.

Conclusions. Analysis of the electrocardiograms (ECGs) of healthy rats after the introduction of the alginate hydrogel into the heart muscle showed that the correct sinus rhythm is maintained, and the QRS-T complexes retain their shape and duration, indicating that the alginate implant does not cause pathological changes in the ECG. It was demonstrated that the alginate implant, when introduced into the myocardial infarction area, is an indifferent substance that does not exacerbate destructive and inflammatory processes and can be used as a carrier for biologically active substances or drugs for delivery to the damaged area. On the 30th day of observation, in the group with CPHE in the alginate gel, the shape of the QRS complex corresponds to the norm, and signs of heart remodeling are minimal, as evidenced by the absence of animals with a registered Q wave. In contrast, up to 40% of animals in other groups show signs of previous transmural myocardial necrosis with the persistence of the Q wave on the ECG.