The experience of radiofrequency ablation of atrial tachycardia focus with the use of high-density myocardial mapping

The article presents a case of successful treatment of focal atrial tachycardia by radiofrequency ablation using high-density myocardial mapping. The aim of the work was to evaluate the possibilities of high-resolution myocardial mapping by EnsitePrecision® navigation system in the treatment of complex arrhythmias. The analysis of clinical data and results of electrophysiological examination of a 29-year-old patient with continuous recurrent focal atrial tachycardia was carried out. The patient was admitted with complaints of heart rate disorders and frequent short attacks of palpitations. According to electrocardiography, frequent short paroxysms of focal atrial tachycardia were revealed. The patient was taken for electrophysiological examination and radiofrequency ablation of the focus of atrial tachycardia. The focus of atrial tachycardia was located in the anterior septal part of the left atrium, which is a rare localization. After radiofrequency ablation tachycardia was terminated, no complications and recurrences were registered. The patient was discharged with the sinus rhythm. Navigation system EnsitePrecision® enables conducting high-density myocardial mapping, which helps to accurately determine the localization of the source of tachycardia. The radiation load on the patient and ablation time are reduced, which reduces the frequency of complications from the procedure

Разработка технологии получения наночастиц на основе PLGA и дипропоксибактериопурпуринимида. Оценка физико-химических и биологических свойств полученной системы доставки

The article describes the process of developing a technology for producing nanoparticles based on a copolymer of lactic and glycolic acids (PLGA) containing dipropoxybacteriopurpurinimide (DPBPI) for photodynamic therapy of malignant tumors of various origins. Technological parameters for optimizing the method in order to obtain nanoparticles with specified characteristics are presented in this paper. As a result, the nanoparticles sample with an average particle diameter of 222.6±2.8 nm; ξ-potential 26.3±4.61 mV; polydispersity index 0.144; the total content of DPBPI in PLGA-DPBPI nanoparticles 13.6% were obtained. In accordance with the developed technique, the batch of PLGA-DPBPI nanoparticles was developed for further biological studies. In vitro experiments on A549 human non-small cell lung carcinoma for DPBPI, delivered as a part of PLGA-DPBPI nanoparticles, and an EL cremophor-based emulsion (CrEL-DPBPI) showed a similar intracellular distribution (concentrated in vesicular cell structures and diffusely distributed in cytoplasm), as well as high photo induced activity and the absence of dark cytotoxicity in case of PLGA-DPBPI nanoparticles. The study of the PLGA-DPBPI nanoparticles specific activity in vivo on the S37 mouse soft tissue sarcoma model showed the selective accumulation of DPBPI in tumor tissue and the almost complete elimination of DPBPI from the body within 48 hours, as well as significant antitumor efficacy in PDT.В статье описан процесс разработки технологии получения наночастиц на основе сополимера молочной и гликолевой кислот (PLGA), включающих дипропоксибактериопурпуринимид (DPBPI) и предназначенных для фотодинамической терапии (ФДТ) злокачественных новообразований различного генеза. В работе подобраны технологические параметры, позволяющие оптимизировать метод получения наночастиц с заданными характеристиками, в результате был получен образец сферических частиц, обладающая средним диаметром частиц 222,6±2,8 нм; ξ-потенциалом –26,3±4,61 мВ; индексом полидисперсности 0,144; общее содержание DPBPI в частицах PLGA-DPBPI составило13,6%. В соответствии с разработанной методикой была осуществлена наработка партии наночастиц PLGA-DPBPI для дальнейших биологических исследований. В экспериментах in vitro на клетках немелкоклеточной карциномы легкого человека А549 для DPBPI, доставленного в клетки с помощью наночастиц PLGA-DPBPI, и эмульсии на основе кремофора EL (CrEL-DPBPI) было показано сходное внутриклеточное распределение (концентрирование в везикулярных клеточных структурах и диффузное распределение в цитоплазме), а также была показана высокая фотоиндуцированная активность и отсутствие темновой цитотоксичности в случае использования частиц PLGA-DPBPI. Изучение специфической активности наночастиц PLGA-DPBPI in vivo на модели саркомы мягких тканей мыши S37 показало селективное накопление DPBPI в опухолевой ткани и практически полное выведение DPBPI из организма в течение 48 ч, а также выраженную противоопухолевую эффективность при ФДТ

Development of the technology for obtaining PLGA and dipropoxybateriopurpurinimide-based nanoparticles. Evaluation of physicochemical and biological properties of the obtained delivery system

The article describes the process of developing a technology for producing nanoparticles based on a copolymer of lactic and glycolic acids (PLGA) containing dipropoxybacteriopurpurinimide (DPBPI) for photodynamic therapy of malignant tumors of various origins. Technological parameters for optimizing the method in order to obtain nanoparticles with specified characteristics are presented in this paper. As a result, the nanoparticles sample with an average particle diameter of 222.6±2.8 nm; ξ-potential 26.3±4.61 mV; polydispersity index 0.144; the total content of DPBPI in PLGA-DPBPI nanoparticles 13.6% were obtained. In accordance with the developed technique, the batch of PLGA-DPBPI nanoparticles was developed for further biological studies. In vitro experiments on A549 human non-small cell lung carcinoma for DPBPI, delivered as a part of PLGA-DPBPI nanoparticles, and an EL cremophor-based emulsion (CrEL-DPBPI) showed a similar intracellular distribution (concentrated in vesicular cell structures and diffusely distributed in cytoplasm), as well as high photo induced activity and the absence of dark cytotoxicity in case of PLGA-DPBPI nanoparticles. The study of the PLGA-DPBPI nanoparticles specific activity in vivo on the S37 mouse soft tissue sarcoma model showed the selective accumulation of DPBPI in tumor tissue and the almost complete elimination of DPBPI from the body within 48 hours, as well as significant antitumor efficacy in PDT

Rotor Drivers in Induction and Maintenance of Atrial Fibrillation

Atrial fibrillation is the most common arrhythmia in clinical practice. It is associated with an increased risk of stroke, chronic heart failure, and sudden cardiac death. Our options of restoring and maintaining sinus rhythm have a very limited effect, both in the case of antiarrhythmic and catheter treatment. Catheter ablation has proven to be a more effective approach than antiarrhythmic therapy. The success rate of the procedure reaches 70%. However, radiofrequency ablation is associated with a risk of complications, with 4.5% of patients likely to develop major complications, including tamponade (1.31%), femoral pseudoaneurysm (0.71%), and death (0.15%). Given the generally recognized dominant role of the pulmonary veins in the induction of atrial fibrillation, their electrical isolation has become the recommended tactic of the catheter approach. In the case of patients with paroxysmal form of atrial fibrillation, the success rate of the procedure reaches 87%. Unfortunately, in the case of persistent forms of atrial fibrillation, the effectiveness of the primary procedure decreases to 28% and reaches 51% with repeated interventions. In addition to the anatomically oriented isolation of the pulmonary veins, a number of strategies have been proposed to reach the secondary zones of atrial fibrillation induction. The results of recent studies on the effectiveness of strategies for ablation of rotor regions and their role in the induction and maintenance of AF may lead to the further development of catheter ablation techniques and an individual radiofrequency ablation approach in a particular patient

Nonfluoroscopic catheter ablation in patients with atrial fibrillation

The article demonstrates available literature data on the nonfluoroscopic catheter ablation of atrial fibrillation (AF). The main disadvantages of standard fluoroscopic catheter ablation are shown. The research results on the use of intracardiac echocardiography are presented. The first experience of using the fluoroscopy-free procedure in Russia as a pilot study is also presented. During the period from December 2017 to December 2019, 28 radiofrequency ablations and 40 pulmonary vein cryoballoon ablations were performed without fluoroscopy using threedimensional imaging and intracardiac echocardiography. Despite the small number of large studies in this area, clinical cases described in the literature, as well as their own results, demonstrate the safety of using three-dimensional imaging in combination with intracardiac echocardiography as an alternative to fluoroscopy. Application of the approach is of undoubted practical interest and requires further study in large studies