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This document provides an overview of current problems and trends in the catheter ablation of atrial fibrillation, summarizes the opinions of specialists, obtained during a web-based electronic survey, on aspects and parameters of radiofrequency ablation. The approaches on improving the efficacy and safety of radiofrequency catheter ablation of atrial fibrillation are provided.

This study presents literature data over the past few years on markers of acute myocardial damage after radiofrequency ablation. Information on markers such as troponin I and T, creatine phosphokinase and its fractions, CRP and interleukins and myoglobin is presented in detail. For each potential myocardial damage indicator, data related to their expression site, chemical basis of each marker and correlation between the degree of damage caused by radiofrequency exposure and the levels of various biomarkers of myocardial damage are provided.Received 12 November 2019. Revised 26 February 2020. Accepted 27 February 2020.Funding: The study did not have sponsorship.Conflict of interest: Authors declare no conflict of interest.Author contributionsConception and study design: O.L. Zajfrid, R.B. Tatarsky, E.S. VasichkinaDrafting the article: O.L. Zajfrid, K.A. Chueva, A.V. Mikhailov Critical revision of the article: O.L. Zajfrid, R.B. Tatarsky, E.S. Vasichkina, I.L. Nikitina, D.S. LebedevFinal approval of the version to be published: O.L. Zajfrid, K.A. Chueva, E.S. Vasichkina, A.V. Mikhailov, D.S. Lebedev, I.L. Nikitina, R.B. Tatarsky

Aim. To analyze the prognostic value of 18 electrocardiographic (ECG) markers of left bundle branch block (LBBB) in predicting left ventricular (LV) reverse remodeling in patients receiving cardiac resynchronization therapy (CRT).Material and methods. The study included 98 patients. Depending on the presence of reverse remodeling during CRT, defined as a decrease in LV endsystolic volume ≥15%, the patients were divided into two groups: non-responders (n=33) and responders (n=65). We selected and analyzed 18 ECG markers included in 9 LBBB criteria.Results. Among the ECG markers significantly associated with reverse remodeling during CRT, the absence of q wave in leads V5-V6 demonstrated the highest sensitivity (92,31%), a negative predictive value (70,59%) and overall accuracy (73,47%). Normal internal deviation interval of the R wave in leads V1-V3 was also associated with the best sensitivity (92.31%), while QS with a positive T in lead aVR — the best specificity (69,7%). Discordant T wave demonstrated the highest positive predictive value (80,33%). Multivariate analysis revealed following ECG signs independently associated with reverse remodeling during CRT: QRS complex duration (odds ratio (OR)=1,022; 95% confidence interval (CI): 1,001-1,043; p=0,040); absence of q wave in leads V5-V6 (OR=4,076; 95% CI: 1,071-15,51; p=0,039); discordant T wave (OR=4,565; 95% CI: 1,708-12,202; p=0,002). These ECG findings were combined into a mathematical model that demonstrated high predictive power (AUC=0,81 [0,722-0,898], pConclusion. For the first time, the diagnostic value of ECG markers of LBBB were analyzed and a mathematical model with ECG signs was proposed to predict reverse remodeling in patients receiving CRT.

Aim. To determine the features of left atrial electroanatomic structure and the arrhythmia substrate in patients with atrial fibrillation (AF) after coronavirus disease 2019 (COVID-19).Material and methods. The pilot study included 20 patients with AF who underwent catheter radiofrequency ablation. Ten patients had COVID-19 and 10 patients were included as a control group. AF substrate was identified using anatomic and bipolar mapping. Zones with following amplitudes were analyzed: 0,75 mV. Left atrial volume was determined based on anatomic map.Results. The groups were homogeneous in AF type, number of patients after prior pulmonary vein isolation, and heart rate during mapping. In the COVID-19 group, there was a higher area of fibrous zones with an amplitude of 0,75 mV (11,6±8,0% vs 45,0±25,0% in the control group, p=0,001). In 7 COVID-19 patients, the posterior wall was isolated due to low-amplitude zones. Of these, three patients underwent surgery for the first time. According to ROC analysis, in patients after COVID-19, fibrous tissue (0,75 mV) — ~30% or less.Conclusion. This study shows that SARS-CoV-2 infection may cause left atrial remodeling in the form of diffuse fibrosis. The arrhythmia substrate in patients after COVID-19 can be localized not only in pulmonary vein mouths, but also in other left atrial areas. This must be taken into account before ablation, even if the procedure is being performed for the first time. It is recommended to perform amplitude mapping for all patients who have had SARS-CoV-2 infection in order to identify fibrous zones and plan the operation extent.

Three clinical cases of 2-year follow-up of young patients with chronic heart failure with a low left ventricular ejection fraction of non-coronarogenic genesis after implantation of the cardiac contractility modulation system are presented. Significant positive dynamics of clinical course and reverse myocardial remodeling according to two-dimensional echocardiography and 2D speckle tracking echocardiography (STE) is shown. The 2D STE technique allowed us to demonstrate the improvement in local contractility of the interventricular septum in the area of implanted electrodes and the remote effect of global contractility improving during 1 year of observation with cardiac contractility modulation.

Aim. To assess various types of electrotherapy and the reasons for its use in patients with implanted cardioverter defibrillators (ICD) for primary prevention of sudden cardiac death (SCD).Material and methods. A retrospective single-site study of 308 patients with implanted cardioverter defibrillators was conducted. Patients were divided into 2 groups: 1 — patients with persistent paroxysmal ventricular tachycardia (VT)/ ventricular fibrillation (VF); 2 — patients without persistent paroxysms of VT/VF. The standard ICD programming protocol was carried out intraoperatively, at 3-4 days after the implantation, then 1 time in 12 months, as well as unscheduled on request. Primary data was collected about paroxysms of ventricular and supraventricular rhythm disturbances, episodes of unmotivated detection of tachyarrhythmias, adequacy of use and types of ICD electrotherapy. The period of dynamic observation was 7 years.Results. The group with an increased risk of persistent paroxysmal VT/VF is patients with ischemic genesis of chronic heart failure (CHF), repeated myocardial infarction, persistent atrial fibrillation (AF), as well as with recorde episodes of unstable VT and ventricular extrasystoles at programming visits. In 54,1% of cases with persistent paroxysms of VT/VF, unjustified detection of ventricular arrhythmias was established. Its causes were: 1) AF with a high heart rate; 2) T-wave detection; 3) sinus tachycardia in the area of detection of VT; 4) atrial flutter with a high heart rate.Conclusion. In patients with primary prophylaxis of SCD, the use of ICD electrotherapy takes place not only due to paroxysms of VT/VF, but also because of both paroxysms of supraventricular rhythm disturbances and other features of rhythm perception by the device. To reduce the number of unjustified triggers during the installation of ICD electrotherapy program in patients with AF/atrial flutter, it is advisable to use a dedicated area of monitor VT and programmed long-term tachycardia detection for adequate rhythm discrimination.

Introduction.From 30 to 92 % of reproductive age women suffer from menstrual pain (algomenorrhea). The effectiveness of drug treatment of this suffering does not exceed 50–70 %. Moreover, it is temporary and accompanied by a high incidence of side effects. Dysfunction of the autonomic nervous system is the basis of the algomenorrhea pathogenesis; it is resulting from chronic exposure to psychogenic factor and adaptive mechanisms decrease in thalamus and hypothalamus which is leading to the nociceptive system excitation. Currently, there are scientifi c studies showing the effectiveness of osteopathic correction of autonomic dysfunction that can eliminate menstrual pain.Goal of research— to justify the osteopathic treatment effectiveness for patients with primary algomenorrhea.Materials and methods.The study included 30 women aged from 15 to 29 years who applied to the gynecological offi ce, diagnosed with primary algomenorrhea and a disease period of 3 to 16 years. They were randomly divided into 2 groups: experimental and control, of 15 people each. The patients of experimental group received osteopathic treatment, the patients of control group received drug therapy only. Osteopathic status was determined in all patients before and after treatment. Pain intensity was assessed by using a visual analogue scale (VAS), the direction of autonomic dysfunction — by using the Kerdo index and the severity of autonomic dysfunction — according to the Wayne questionnaire.Results.Dura mater RBN S (93 % of patients) and RBN in the visceral chest region (70 %) were specifi c regional somatic dysfunctions. The remaining regional somatic dysfunctions were common less than in 50 % of patients. Specifi c local somatic dysfunctions (LD) in patients with algomenorrhea were uterus LD (73 %) and mediastinum LD (70 %). Due to osteopathic treatment, the number of regional and local somatic dysfunctions was decreased in the experimental group. Autonomic dysfunction severity and pain syndrome intensity were decreased as well.Conclusion.The results of the study allow us to recommend osteopathic treatment for patients with primary algomenorrhea.

Background: Bromhexine hydrochloride has been suggested as a TMPRSS2 protease blocker that precludes the penetration of SARS-CoV-2 into cells. We aimed to assess the preventive potential of regular bromhexine hydrochloride intake for COVID-19 risk reduction in medical staff actively involved in the evaluation and treatment of patients with confirmed or suspected SARS-CoV-2 infection. Methods: In a single-center randomized open-label study, medical staff managing patients with suspected and confirmed COVID-19 were enrolled and followed up for 8 weeks. The study began at the initiation of COVID-19 management in the clinic. The study was prematurely terminated after the enrollment of 50 participants without a history of SARS-CoV-2 infection: 25 were assigned to bromhexine hydrochloride treatment (8 mg 3 times per day), and 25 were controls. The composite primary endpoint was a positive nasopharyngeal swab polymerase chain reaction (PCR) test for SARS-CoV-2 or signs of clinical infection within 28 days and at week 8. Secondary endpoints included: time from the first contact with a person with COVID-19 to the appearance of respiratory infection symptoms; the number of days before a first positive SARS-CoV-2 test; the number of asymptomatic participants with a positive nasopharyngeal swab test; the number of symptomatic COVID-19 cases; adverse events. Results: The rate of the combined primary endpoint did not differ significantly between the active treatment group (2/25 [8%]) and control group (7/25 [28%]); P=0.07. A fewer number of participants developed symptomatic COVID-19 in the treatment group compared to controls (0/25 vs 5/25; P = 0.02). Conclusion: Although the study was underpowered, it showed that Bromhexine hydrochloride prophylaxis was associated with a reduced rate of symptomatic COVID-19. The prophylactic treatment was not associated with a lower combined primary endpoint rate, a positive swab PCR test, or COVID-19. (ClinicalTrials.gov number, NCT04405999)

Aim. To determine quantitative criteria for assessing the therapeutic benefits and the most informative time frames after cardiac resynchronization therapy (CRT) to assess its long-term effectiveness (1, 2, 3 years of follow-up) based on retrospective analysis. To assess the CRT effectiveness, parameters of left ventricular (LV) reverse remodeling and signs characterizing the clinical CRT response were considered.Material and methods. This single-center, retrospective, non-randomized study included data from 278 patients with implanted CRT devices. Quantitative criteria for assessing CRT effectiveness were determined using a two-step cluster analysis of patients 1, 2, and 3 years after CRT by LV reverse remodeling parameters.Results. In the dataset with satisfactory division accuracy, after the first year, two clusters were identified, which are conventionally named as “non-responders” and “responders”. Two and three years after therapy, patients were classified into three clusters: “non-responders”, “responders” and “super-responders”. For the obtained clusters, we found cutoff values for LV reverse remodeling parameters, which can be used as criteria for response to therapy.The study identified the most informative time frames for assessing the postoperative CRT effectiveness 1, 2, 3 years after the surgery. At the same time, the clinical response to therapy is manifested earlier in comparison with the reverse LV remodeling.Despite the high divisibility of patients into responders and non-responders, predictive models of CRT effectiveness created using the available data from standard diagnostic protocols for heart failure patients have insufficient accuracy to be used for making decisions on therapy appropriateness. This circumstance indicates the need to receive additional data to improve the forecasting quality.Conclusion. The study revealed a period for assessing the clinical response and changes in LV reverse remodeling after CRT surgery, which is important for the optimal choice of postoperative therapy. It has been shown that in most cases, one year after surgery is sufficient to assess the clinical response, and the process of LV reverse remodeling can last up to two years on average.When assessing the CRT effectiveness by reverse remodeling, along with a change in LV end-systolic volume (ESV), it is necessary to take into account LV end-diastolic volume (EDV) changes. The change in LV ejection fraction showed a significantly lower value among the analyzed parameters in assessing the CRT effectiveness. Based on the cluster classification of patients, a dividing rule was established for responders and non-responders in the first and second years after surgery with an accuracy of 97%: a decrease in LV ESV and EDV by 9% or more compared to preoperative values.

His bundle pacing (HBP) implements physiological impulse propagation along the cardiac conduction system and can serve as an analogue of both right ventricular and biventricular pacing. This review highlights clinical anatomy issues related to HBP; the technique of lead implantation in the His position is considered. We also describe the electrophysiological basis of HBP, possibilities of lead extraction, indications for implantation, and prospects for further development of the technique. HBP is a promising direction in cardiology, which in the future may fundamentally change the algorithms for managing patients with heart failure and conduction disorders.

Aim. The results presented, of subanalysis of the catheter ablation (CA) registry in atrial fibrillation (AF) with the patients properties, specifics of CA and treatment results, in Russia comparing to European countries.Material and methods. During 2012 to 2015, totally 3742 patients included to the registry, of those 477 in Russia. In 467 Russian patients (males 56,5%; mean age 58,5 y. o.) CA AF was done. During one year 392 patients were followed up. Minimum requirements to follow-up: routine ECG registration and non less than one contact after 12 months passed.Results. In Russian patients there were more common obesity (46,1% and 29,2%, pConclusion. In real clinical setting, high efficacy of CA AF was shown, resistant to antiarrhythmic therapy. In most of Russian patients there were cardiovascular comorbidities. There was lower rate of reported adverse events in Russian centers of interventional treatments.

Aim. To evaluate diagnostic significance of non-invasive methods of myocarditis diagnostics. Material and methods. To the study, 141 patient included with suspected myocarditis (104 males, 37 females; age 11-69, mean age 42,7±13,7 y. o.). All patients, together with clinical assessment, underwent standard echocardiography, magnete resonance tomography (MRI) of the heart with contrast enhancement and endomyocardial biopsy with histological and immunohistochemical analysis. Also, the levels of circulating cardiotropic autoantibodies, troponin I and C-reactive protein were measured. Results. There were no significant differences between patients with myocarditis and dilation cardiomyopathy (DCM) in analysis of clinical, anamnestical and standard laboratory data. The differences found, in levels of circulating cardiospecific autoantibodies in myocarditis patients and DCM comparing to almost healthy donors. However the profile of autoantibodies in myocarditis and DCM patients differed only by the level of autoantibodies to cardiac myosin (χ 2 =6,0; р=0,014), cytoplasmic antigen of cardiomyocytes CoS-05-40 (χ 2 =10,2; р=0,001) and the adenine nucleotide translocator protein ANT (epitope EGS) (χ 2 =10,7; р=0,001). Sensitivity of MRI for myocarditis diagnosis is 67%. In acute myocarditis MRI sensitivity is significantly higher than in chronic inflammation: 85% and 63%, respectively. In chronic borderline myocarditis the sensitivity is no more than 55%. Conclusion. Low diagnostic significance of clinical and anamnestic data confirmed, and the data of standard laboratory and instrumental investigation, in diagnostics of myocarditis. In patients with myocarditis and DCM there was a specific autoantibodies profile found, different from that of almost healthy donors. MRI shows the highest sensitivity for acute myocarditis. In chronic one, sensitivity depends on inflammation activeness, making necessary the biopsy.

Aim. To find out the clinical and electrophysiological predictors of recurrent ventricular tachyarrhythmias (VTA) after catheter homogenization of post-infarction scar areas. Material and methods . Patients included, with myocardial infarction (MI) in anamnesis and documented sustained VTA, regardless effective treatment by implantable cardioverter-defibrillator. Totally, 72 patients included (mean age 64±13 y.o.), of those 63 males with postinfarction VTA. In 12 cases there were“electrical storms” demanded urgent catheter management. In such patients, the extended catheter homogenization of the scar was performed, that is ablation of all conduction channels, anomalous potentials and surrounding ablation of infarction zone. Patients were selected to 2 groups according to recurrent VT in post-surgery period. First group included 27 (37%) VTA recurrent patients, mean age 62±10 y.o. Second group included 45 patients (63%) with non tachyarrhythmias recurrence, mean age 63±12 y.o. The evaluation was done, of the selected parameters with the aim to define predictors of rhythm disorders recurrence. Results. Main clinical predictors of VTA recurrence after catheter ablation were the duration of post MI period and its anterior localization. Full area of the scar surface (bipolar voltage lower 1,5 mV) was comparable in patients with recurrent VT and with none (66±51 cm 2 vs 82±49 cm 2 ). However the area of the dense scar (bipolar amplitude ≤0,5 mV) and percent of the dense scar in relation to entire scar was significantly smaller in the recurrence group (group 1 — 23±22 cm 2 and 24±18%, in group 2 — 41±22 cm 2 and 45±21%; p

Aim. Comparison of efficacy and safety of the robotic catheter and manual catheter ablation in management of patients with persistent atrial fibrillation (PsAF). Material and methods . In the study, 80 patients included, with PsAF. They were randomized to groups of manual ablation (MA) and robotic ablation (RA). After ablation, patients were followed up during 1 year every 3 months. Sinus rhythm retention was evaluated with Holter 24-hour ECG monitoring and 12-channel ECG. As efficacy criteria, the absence was taken of registered paroxysms of atrial fibrillation and other tachiarrhythmias lasted 30 sec and more. As primary endpoint, the absence was taken of any atrial tachiarrhythmias (AFib/AFlut) after the ablation procedure during 12 months, with every 3 months ECG monitoring. As secondary endpoints the following were taken: complications rate, duration of procedure and x-ray exposition, rate of recovery of conduction through the ablation line in acute phase (in 30 min post ablation) with intravenous ATP. Results. Mean procedure time and x-rays exposition in MA group was 164±28 min and 45±14 min, respectively. Mean duration of procedure in RA was 200±35 min (p

Aim. By non-invasive methods, to assess relations of the zone of late electrical activation with changes in the left ventricle (LV) myocardium structure in patients — candidates for cardiac resynchronizing therapy. Material and methods. Totally, 37 patients included, with III functional class of chronic heart failure (CHF). In all patients, there was complete His left bundle branch block (LBBB) with QRS width 205 (190; 215) ms. Non-invasive electrophysiological mapping (NEM) was done with the “Amycard01C EP LAB” (EP Solutions SA,Switzerland), and magnetic-resonance imaging (MRI). At the first step, multichannel electrocardiography (ECG) was done. At the second step, MRI was done (MAGNETOM Trio A Tim 3 T, Siemens AG,Germany) with intravenous contrast “Gadovist” load. Changes inLV myocardium structure (post-inflammatory fibrosis or scar tissue) were evaluated by segments, within the delayed MRI contrasting. At the third stage, individual models of ventricles were built up. Activation ofLV epicardium in LBBB was evaluated by NEM. Results. Most oftenly the zone of late activation by NEM was found in the basal region on the border of posterior and lateral LV segments — 17 patients (46%) and in basal lateral LV segment — 8 (21%). By MRI, only post inflammatory fibrosis was found in 21 patient, among them in 5 the area of fibrosis was located on LV epicardium and overlapped the zone of late activation by NEM. Among 12 patients with ischemic heart disease 2 had scar onLV epicardium overlapping with the late activation zone. No one of 4 patients with combination of post-inflammatory fibrosis and ischemic scar did not show overlap of structural changes on the epicardium with the late activation zone. Conclusion. Combination of NEM and MRI in pre-operational period of patients investigation make it to relate structural changes inLV myocardium with the zone of its late electrical activation.

Aim. To perform the comparative analysis of atria morphometry and histological composition of myocardium in men and women with structural pathology of the heart. Material and methods . As the materials, case histories were used and autopsy records of 41 patient, age 43 to 88 y.o., 23 males and 18 females; of those 28 had coronary heart disease, 10 — other cardiovascular disorders, 3 — non-cardiac pathology. Organometry was done of the atria in 23 zones. Paraffin slices of all 23 localizations, as of the sinus and atrio-ventricular nodes were colored with hematoxiline and eosine, and by van Hison. Morphometry was done, with assessment of ganglia and nervous fibers localization density, relative square of fibrosis and lipomatosis areas, mean relative square or antigens expression areas in ganglia and nervous fibers. Comparison was done, of morphometric and clinical parameters in men and women. Results. In men, there was statistically significantly higher mean cardiac mass, distance between inferior pulmonary veins, thickness of the left atrial wall, the cuff height of inferior right pulmonary vein (p

Aim . To evaluate an extent of left arrial (LA) electroanatomical substrate (EAS) by the method of high density contact mapping in patients with atrial fibrillation (AF) and estimate its impact on recurrence rate following circular radiofrequency pulmonary veins (PV) isolation in prospective observational study. Material and methods. Totally 181 high symptomatic subjects with paroxysmal (142 pts) and persistent (39 pts) AF, who underwent circular RF PVI were enrolled. We created and prospectively analyzed LA electroanatomical high density bipolar maps. Bipolar signals ≤0.75mV, associated with local conduction velocity delay

Aim. To assess the clinical course and cardiac reverse remodeling in patients with heart failure (HF) with reduced ejection fraction (HFrEF) receiving cardiac contractility modulation (CCM) therapy.Material and methods. Fifty-five patients (mean age, 53±11 years, 46 males) with NYHA class II-III HFrEF (ischemic etiology in 73% of patients), sinus rhythm, QRS25% and

Endomyocardial biopsy (EMB) is one of diagnostical tools for arrhythmogenic dysplasia of the right ventricle (ADRB). However sensitivity and specificity of EMB relay on the methodics of its performing. Aim. To compare “focus-guided” and “voluntary” EMB in diagnostics of ADRB in patients, scheduled for catheter ablation of ventricular rhythm disorders. Material and methods. To retrospective study 122 patients included, among those scheduled for catheter ablation of ventricular tachicardia and\or sympthomatic ventricular extrasystoly, underwent EMB (64 males, mean age 39±14 y.). Patients were selected to 2 groups: 1) 44 patients (36%) with “focus-guided” biopsy (minimum 1 fragment of endomyocardium from the area(s) of ectopy); 2) 78 patients (64%) with “voluntary” EMB (specimens taken from any area except the focus). Results. Sixteen (13,1%) patients took the definite dignosis of ADRB according to 2010 Criteria. Short-term effect of ablation reached 69,7% of patients, much less efficacy had ADRB group (43,8%). Sensitivity and specificity of EMB in the big criteria of ADRB revealing, by histology, was higher in the group with “focus-guided” EMB, comparing to the “voluntary” group (100% and 91,7% vs. 80% and 81,4%, respectively). Conclusion. To improve sensitivity and specificity of EMB in ADRB diagnostics it is aimful to take myocardium specimens from the area of researched ventricular ectopy.

Aim . To study the specifics of clinical course and outcomes of higher degree AVB, developed due to inflammatory changes of myocardium in infants, during three years follow-up. Material and methods . For the assessment of AVB specifics in current myocarditis we have summarized the investigation data of 6 patients younger than 1,5 y. o.; mean age 10,0±4,5 months (3 to 16 months). In all clinical cases we performed the analysis of medical source documents with outcopying of pregnancy data, analysis of cardiotocography (CTG) data and ultrasound examination (USE) of the fetus (to rule out inborn cause for AVB), stages of the growth and development of a child, diseases anamnesis. The complex laboratory and instrumental investigation was done, including evaluation of biochemical markers of inflammation and serum markers of myocardial damage, electrocardiographic (ECG) and echocardiographic (EchoCG) studies. Results. Mean follow-up was 23,3±10,4 months (from 9 to 35 months). On treatment, all patients had tendency for the decrease of cardiac specific enzymes, the decrease of heart failure functional class and positive EchoCG dynamics by the end of the first year. However, AV-conduction disorders of the heart in all patients had irreversible course. Permanent pacemaker (PPM) was set up in two cases, in 6 and 14 months after diagnosis. Conclusion. In infants the AV conduction disorders that develop in myocarditis, show irreversible pattern of clinical course.

Aim. To assess the 2-year prognosis of patients with heart failure with reduced ejection fraction (HFrEF) receiving cardiac contractility modulation (CCM).Material and methods. This single-center observational study included 55 patients (46 men, mean age 53±11 years) with NYHA class II-III HFrEF receiving optimal medical therapy, with sinus rhythm, QRS styear and every 6 months during the 2ndyear of observation. The primary composite endpoint was mortality and heart transplantation. Secondary composite endpoints included death, heart transplantation, paroxysmal ventricular tachycardia/ ventricular fibrillation, hospitalizations due decompensated HFResults.The one-year and two-year survival rate was 95% and 80%, respectively. Primary endpoint was observed in 20% of patients. NYHA class III and higher levels of N-terminal pro-brain natriuretic peptide (NTproBNP) were associated with unfavorable prognosis (p=0,014 and p=0,026, respectively). NTproBNP was an independent predictor of survival (p=0,018). CCM contributed to a significant decrease in hospitalizations due to decompensated HF (pstyear. The predictor for the secondary composite endpoint was NTproBNP (p=0,047).Conclusion. CCM is associated with a significant decrease in hospitalization rate due to decompensated HF. The 2-year survival rate of patients with NYHA class II-III HF receiving CCM was 80%. The NTproBNP level was an independent predictor of survival in patients receiving CMM for 2 years. Further longer-term studies of the CCM efficacy are required.

Aim. Catheter ablation (CA) is an effective approach for rhythm control in atrial fibrillation (AF), however antiarrhythmic therapy (AAT) remains important. There is a lack of data about long-term AAT use after CA. This study evaluates AAT after CA for AF.Material and methods. In 2012-2016, EURObservational Research Programme of Atrial Fibrillation Ablation Long-Term (EORP AFA L-T) registry was conducted, which included 476 Russian patients (57,1% — men; mean age — 57,1±8,7 years). The follow-up after CA was 12 months (available in 81,9% of patients). The use of AAT was evaluated prior to hospitalization, during hospitalization for CA, as well as at 3, 6 and 12 months of follow-up.Results. Prior to CA, 439 (92,2%) patients received AAT During CA, 459 (96,4%) patients were treated with AAT. After CA, AAT was used by 463 (97,3%), 370 (94,8%), and 307 (78,7%) patients at 3, 6 and 12 months of follow-up, respectively. There was no arrhythmia recurrence in 187 (47,9%) subjects. Among these patients, 40 (21,4%) received class IC or III AAT. The peak of AAT use was found for class IC agents within 3 months after CA (PConclusion. The frequency of AAT use after AF ablation is significantly reduced. However, there is a cohort of patients without documented arrhythmia recurrence still receiving AAT, which requires special attention of physicians. There were no clinical predictors of continued AAT in subjects without arrhythmia recurrence.

Aim. To evaluate the clinical and electrophysiological picture of binodal disease in children, as well as studying the clinical course of this disease. Methods. To study the clinical and electrophysiological picture of autonomic binodal disease, 426 patients under 18 years old were examined; the average age was 15.35±2.43 years (3-17.9). Patient’s complaints, medical history were examined, ECG, 24-hour ECG, stress ECG (treadmill or bicycle test), echocardiography, transesophageal electrophysiologic study were performed. In the case of a combination with pathological signs of sinus node dysfunction and atrioventricular node conduction disorders with the normalization of all parameters after the atropine administration, hypervagotonic binodal dysfunction was diagnosed. To assess the clinical course of the disease, a group of 72 children was selected, who were monitored repeatedly. Mean follow-up duration was 33 months. Results. During the study period, sinus node dysfunction and atrioventricular blocks completely resolved in 14 (19.44%), seen as normal clinical picture with no complaints, normal heart rate, no signs of sinoatrial block or atrioventricular block, normalization of Wenckebach point position. Another 35 (48.62%) had only one node dysfunction resolved (either sinoatrial or atrioventricular - Wenckebach point position within the age normal values and/or atrioventricular block resolved). In 23 (31.94%) - deterioration of the sinus node and atrioventricular node dysfunction was observed. Conclusion. There are significant differences in the frequency characteristics of heart rhythm and electrophysiological parameters of sinus node function in children with a favorable clinical course of binodal disease and progressive course of the disease.

The aim of the study was to analyze the changes in the human breath acetone concentration during stress testing. Using the portable mass spectrometer we obtained recordings of acetone concentration during stress testing on bicycle ergometer for groups of healthy subjects, athletes and patients with congestive heart failure (CHF). As a result, we found significant differences (p < 0.05) of some parameters of acetone concentration that differ significantly between healthy subjects and patients with CHF. In addition, a parameter that allows classifying patients with CHF into subgroups based on the functional class of CHF was obtained. The results obtained in this study may be useful for the objectification of the functional status of patients with CHF.

We studied behavioral reactions of rats after injection of subconvulsive dose of kainic acid into the frontal cortex and mitochondrial respiration in the hippocampus and frontal and temporal cortex 17-20 days after administration of kainic acid. Retention of acquired habit and the dynamics of its extinction in experimental rats were close to those in the control group. Changes in mitochondrial function were observed only in the region of kainic acid injection: activation of phosphorylating respiration during oxidation of succinate. Presumably, the detected activation of energy metabolism in the frontal cortex indicates functional restructuring in mitochondria, aimed at compensation of disorders caused by the neurotoxin.

Cognitive processes and functional state of mitochondria in brain structures of Wistar rats were studied after intrahippocampal injection of kainic acid, an agonist of glutamate receptors. A single administration of 0.25 microg kainic acid into the dorsal part of the left and right hippocampi affected task retrieval and decreased inhibition of unrewarded responses. The injection of 0.75 microg kainic acid induced recurrent seizures and completely disorganized animal behavior. The functional state of mitochondria, as an important marker of excitotoxicity, was studied after intrahippocampal injections of kainic acid in the same doses. Kainic acid at 0.25 microg proved to activate the oxidative phosphorylation in hippocampal mitochondria. A higher (epileptogenic) dose of kainic acid inhibited mitochondrial respiration in the frontal cortex, but had an insignificant effect on mitochondrial respiration in the hippocampus. The disturbed interaction between the hippocampal system and frontal cortex after kainic acid administration can be the main factor of the revealed cognitive dysfunctions.

The expression of synaptophysin (vesicular protein) and mGluR5 (metabotropic glutamate receptor) genes was studied 3, 7, and 20 days after cainic acid injury of the dorsal hippocampal area in Wistar rats. The expression of both genes was characteristically reduced in the hippocampus. Twenty days after the exposure the expression of mGluR5 in this brain area reached the control level, while synaptophysin expression remained low. An opposite trend was observed in the frontal cortex: synaptophysin expression 20 days after exposure did not differ from the control, while mGluR5 expression was reduced. The peculiar time course of both genes’ expression in the hippocampus and frontal cortex indicates the involvement of the frontal cortex in mechanisms of functional recovery after hippocampal injuries.