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Aim: To evaluate the efficacy of cardiac resynchronization therapy (CRT) in patients with chronic heart failure (CHF) associated with cardiac dyssynchrony and to identify the factors that influence the CRT efficacy., Material and Methods: This retrospective study included 155 patients after implantation of CRT devices. The CRT devices with a built-in cardioverter-defibrillator (CRT-D) and without it (CRT-P) were implanted in 139 (89.7%) and 16 (10.3%) patients, respectively. The follow-up period was 52.37±35.94 months. Based on the study results, two groups of patients were formed depending on the presence of a clinical response to CRT, responders and non-responders. The factors that influenced the clinical response to CRT were studied. The effect of the baseline state of patients on the effect of therapy was assessed. The need for CRT optimization and a possibility of using electrocardiographic criteria for that purpose were studied. Modern devices and leads for CRT, their functional capabilities and their influence on the CRT efficacy were characterized. Statistical analysis was performed with an IBM SPSS Statistics 21.0 (Chicago, USA) package., Results: CRT implantation with the left ventricular lead placement according to the traditional technique, through the coronary sinus, was successful in 130 (87.9%) patients. Difficulties with the left ventricular lead placement were noted in 13 (8.3%) patients when other techniques were used. After 6 months, a hemodynamic and clinical response was observed in 112 (72.2%) patients, and no positive response in 43 (27.8%). The increase in left ventricular ejection fraction in the responder group was more than 21.8±3.7%, which was associated with an improvement of the 6-minute walk test results. Th clinical response was significantly influenced by the possibility of stimulation from the basal parts of the heart; the use of more modern devices for CRT and quadripolar left ventricular leads; timely CRT optimization; and persistent dyssynchrony in non-responders. During the follow-up period, 34 (21.9%) patients died. The death rate in the non-responder group was significantly higher than in the responder group, 18 (41.3%) vs. 16 (14.3%), p=0.001. The main cause of death in the group of non-responders was CHF. Heart transplantation was performed in 3 (1.9%) patients., Conclusion: CRT increases the life span and improves the quality of life in patients with CHF and cardiac dyssynchrony. There was a group of patients with no benefit from CRT in this study. Modern devices allow increasing the number of patients who benefit from CRT. Periodic optimization of CRT is necessary. When optimizing CRT, it is possible to use electrocardiographic criteria of effectiveness: duration of the QRS complex and changes in the position of the electrical axis of the heart.

Bucky gel electrodes are composed of morphology-determining polyvinylidene difluoride (PVDF) filled with carbon nanotubes (CNT). The electrodes are commonly fabricated via the casting of a CNT dispersion containing PVDF and ionic liquid. In this study, several pore-forming additives such as polyethylene glycol (PEG), dibutyl phthalate (DBP), and the common ionic liquid BMIMBF4 were used to control the morphology of the bucky gel electrodes. The crystalline phase type and content of PVDF in the electrodes were determined by FT-IR and DSC, respectively. SEM revealed a sponge-like structure in the case of the use of BMIMBF4 and a spherulite structure if PEG and DBP were used as additives. A strong influence of morphology on the anisotropic increase in the volume of electrodes upon impregnation with electrolyte was observed. The PEG-based electrode elongated more than the others, while the BMIMBF4-based electrode thickened to a greater extent. Ionic actuators were fabricated to experimentally reveal the effect of electrode morphology on their electromechanical efficiency. A high-precision vat photopolymerization technique was used to fabricate identical ionic membranes and minimize their influence on the properties of the actuators. The electrodes were characterized by the same porosity and electrical capacitance, while the actuators differ significantly in performance. As a result, a simple method of using pore-forming additives made it possible to increase the maximum deformation of bucky gel ionic actuators by 1.5 times by changing the morphology of the electrodes.

Two types of poly(5-phenyl-2-norbornene) were synthesized via ring opening metathesis and addition polymerization. The polymers sulfonation reaction under homogeneous conditions resulted in ionomer with high sulfonation degree up to 79% (IEC 3.36 meq/g). The prepared ionomer was characterized by DSC, GPC, 1 H NMR and FT-IR. Polymers for electromechanical applications soluble in common polar organic solvents were obtained by replacing proton of sulfonic group with imidazolium and 1-methylimidazlium. Membranes were prepared using the above-mentioned polymers and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4), as well as mixtures with polyvinylidene fluoride (PVDF). Mechanical, morphological, and conductive properties of the membranes were examined by tensile testing, SEM, and impedance spectroscopy, respectively. Dry and air-stable actuators with electrodes based on SWCNT were fabricated via hot-pressing. Actuators with membranes based on methylimidazolium containing ionomers outperformed classical bucky gel actuator and demonstrated high strain (up to 1.14%) and generated stress (up to 1.21 MPa) under low voltage of 2 V.