Atrial fibrillation (AF) remains one of the most common arrhythmias and a significant sociomedical problem, the prevalence of which is steadily increasing as the population ages. AF is associated with a high risk of stroke, heart failure, cognitive impairment, and a significant reduction in quality of life. It also creates a significant economic burden due to both direct medical costs and indirect losses. Current strategies for managing patients with AF are based on a comprehensive approach, including stroke risk stratification, the use of direct oral anticoagulants, control of associated risk factors, and the selection of optimal treatment strategies. Emerging data demonstrate the benefits of early rhythm control strategies, which help reduce cardiovascular events, slow atrial remodeling, and decrease the number of hospitalizations. However, adherence to treatment remains low, and the availability of elective cardioversion, transesophageal echocardiography, and catheter ablation varies significantly between regions.

Promising areas for improving care, which are highly cost-effective due to a reduction in hospitalizations and serious complications, include the creation of specialized centers for the management of AF patients, the development of telemedicine and remote monitoring, the expansion of educational programs for inpatient and outpatient specialists, increased availability of elective cardioversion and catheter ablation, and the use of artificial intelligence technologies. A comprehensive and systemic approach focused on early intervention, modification of risk factors, active rhythm control, and adherence monitoring is a key tool for improving the quality of care for patients with AF and reducing the burden on the healthcare system.

Aim. Morphological search for an arrhythmogenic substrate of coronavirus disease 2019 (COVID-19) in atrial fibrillation (AF).

Material and methods. The study included 312 patients with confirmed COVID-19 as follows: 274 who died during the acute phase and 38 post-acute patients who recovered from the disease and required endomyocardial biopsy to diagnose cardiovascular pathology. The morphological study included histological and immunohistochemical analysis with quantitative morphometry (CD3, CD68, HLADR, VEGF, MHC I, Ang1, C1q, SARS-CoV-2 spike, and enterovirus VP1) and statistical processing with logistic regression modeling and calculation of odds ratios for AF predictors.

Results. In the acute COVID-19 phase, AF was associated with ischemic microthrombosis (odds ratio (OR)=3,89) and focal necrosis (OR=2,62) with prior cardiomyocyte hypertrophy (OR=4,17). Among clinical factors, the most significant were diabetes, heart failure, and lymphopenia. The created model demonstrated high accuracy (ROC-AUC=0,944). In the post-acute period, AF was associated predominantly with dilated cardiomyopathy (OR=2,16) and myocarditis with enterovirus VP1 expression in cardiomyocytes, the vascular wall, and the inflammatory infiltrate in all cases, as well as persistent SARS-CoV-2 spike expression in macrophages. Low vascular expression of Ang1 and VEGF, as well as moderate macrophage infiltration, were more common in patients without AF (ROC-AUC=0,942).

Conclusion. The combination of infection with cardiac comorbidities and systemic inflammation with ischemic myocardial necrosis increases the AF risk in the acute period. In the post-acute period, AF pathogenesis is due to incomplete myocardial repair with macrophage infiltration and virus persistence.

Aim. To assess the impact of various pathological processes on atrial fibrillation (AF) pathogenesis.

Material and methods. In 42 patients died from various diseases, the abdominal wall fat thickness was measured. In addition, the hearts and previously removed epicardial fat (EF) were weighed, and the heart-to-EF mass ratio was calculated. In an additional 52 patients, myocardium was examined from the areas of the crista terminalis, Bachmann’s bundle, and the upper and lower posterior left atrial wall between the pulmonary vein orifices. Seventeen of these patients had long-standing persistent AF, and seven had paroxysmal AF. Immunohistochemistry (IHC) was performed with anti-collagen I and III, and anti-Isl1 antibodies, and immunofluorescence was performed with an Isl1/desmin cocktail.

Results. No correlation was found between EF mass, fat pad thickness, and AF (p=0,85, r=-0,029 and p=0,09, r=-0,29, respectively). The mean relative area of fibrous tissue in patients without cardiovascular disease in various atrial areas ranged from 6,0±4,1% to 9,9±6,3%, differing significantly across all atrial areas in the group with long-standing persistent AF (p<0,05). Atrial amyloidosis was detected in only 3 cases. A strong correlation between AF and collagen III was determined (r=0,869, p<0,01). IHC detected Isl+cardiomyocyte stem cells.

Conclusion. A significant association was found between AF and atrial fibrosis severity, which is caused by the deposition of collagen III rather than collagen I. AF was found to be unrelated to epicardial fat mass, obesity, and amyloidosis. The detection of cardiomyocyte stem cells in the atria of elderly patients open the potential for cell therapy.

The ligament of Marshall as a vestigial structure plays a key role in arrhythmogenesis due to the combination of preserved muscle fibers with abnormal automaticity and dense autonomic innervation. Its elimination leads to an increase in the effectiveness of interventional treatment of persistent atrial fibrillation and also prevents postoperative atrial fibrillation and ventricular arrhythmias.

Aim. To evaluate parameters of the systemic inflammatory response in myocarditis in patients with atrial fibrillation.

Material and methods. The study sample included 63 patients undergoing inpatient interventional treatment for atrial fibrillation. Of these, 49 (77,8%) were men. The median age was 46 (39; 54) years. During the catheter procedure, all patients underwent endomyocardial biopsy, followed by histological diagnosis. The role of systemic inflammation parameters in patients with and without myocarditis was retrospectively assessed.

Results. Chronic myocarditis was detected in 30 patients (46,1%). The systemic inflammatory response index (SIRI) (p=0,04), total systemic inflammation index (SII) (p=0,02), and monocyte-to-lymphocyte ratio (MLR) (p=0,02) were significantly higher in the group without myocarditis. ROC curves for these parameters were analyzed. Multiple regression analysis revealed no predictive effect of these factors on myocarditis.

Conclusion. The SIRI, SII, and MLR values were significantly higher in patients without myocarditis. The MLR was higher in patients with stage 2 and higher myocardial fibrosis. The SIRI and MLR were significantly lower in patients with higher EHRA score.

The leading risk factors for atrial fibrillation (AF) include advanced age, structural heart disease, high blood pressure, and excessive alcohol use. In other cases, predictors of AF cannot be identified, reflecting the genetic basis of AF. Genetic predisposition increases the risk of AF at a young age by 40%. AF is not strictly hereditary but rather a multifactorial disorder. To date, more than 160 AF-associated genetic loci have been identified based on several studies, including Genome-Wide Association Studies (GWAS). These studies have revealed that AF has a complex genetic architecture. Studying the genetic basis of AF may identify new molecular mechanisms of AF and, as a result, may improve the quality of existing treatments and develop novel therapeutic approaches for isolated AF. This can ensure a more personalized approach and reducing healthcare costs. The aim of this literature review is to present the latest advances and discoveries in the field of AF genetic polymorphism.

This paper analyzes Russian and international literature to determine the diagnostic efficacy of radioisotope methods with various radiopharmaceuticals in patients with atrial fibrillation (AF).

We search for publications in PubMed and Elibrary databases covering the period 20002025 focused on the use of radioisotope methods with various radiopharmaceuticals. This review highlights the potential of radioisotope diagnostic methods such as singlephoton emission computed tomography and positron emission tomography with various radiopharmaceuticals in patients with AF. The diagnostic and prognostic aspects of radioisotope technologies for persistent and paroxysmal atrial fibrillation are discussed. The contribution of [123I]-MIBG scintigraphy in planning interventional treatment for AF is noted. Radioisotope imaging makes a significant contribution to diagnosing the causes of arrhythmia and has prognostic value in predicting adverse events and treatment effectiveness.

Due to the high prevalence of atrial fibrillation (AF), including subclinical forms, the search for novel approaches to screening for this arrhythmia, monitoring symptoms, and effective methods for monitoring therapy adherence is becoming increasingly important. Along with implantable monitors, modern digital methods for personalized rhythm monitoring are being used to diagnose AF: wireless recorders, smart devices, mobile assistants, and other technologies. This paper provides a comparative analysis of the most common personal monitoring methods for AF, developed to assess disease progression, manage symptoms, and prevent complications. Modern technologies for improving medication adherence in various clinical patient groups are also discussed. The authors present results on the development of original mobile application for patients with AF.

Acute cerebrovascular accidents and other thromboembolic events pose a serious challenge in the treatment of patients with atrial fibrillation (AF). Arrhythmias are known to be an independent predictor of an increased risk of stroke and other systemic complications compared to the general population. At the same time, AF is associated with a significantly increased risk of systemic thromboembolism, regardless of clinical form and symptom severity. Effective stroke prevention requires a comprehensive approach, including timely diagnosis, treatment, and risk factor management, as well as the development of novel interventional methods aimed at reducing the risk of thromboembolic events in various AF forms.

In the treatment of patients with atrial fibrillation (AF) and atrial flutter (AFL), the best results are achieved using a comprehensive approach. This facilitates the selection of the optimal management strategy for each individual patient based on current clinical guidelines. Cardioversion is a crucial component of the rhythm control strategy, aimed at both managing symptoms and improving the patient’s prognosis. Selecting the optimal method for restoring sinus rhythm, proper patient preparation, including anticoagulant therapy, and the correct implementation of all procedure stages are essential for achieving an effective and safe outcome. This paper discusses methods for terminating AF and AFL, and provides guidelines for strategies for restoring sinus rhythm and anticoagulant therapy in cardioversion in various clinical situations.

Aim. To assess how adjustment of rate control therapy in permanent atrial fibrillation (AF) affects beat-to-beat hemodynamic metrics derived from continuous beatto-beat blood pressure monitoring.

Material and methods. The study included 32 patients with permanent non-valvular AF (69,5±12,0 years; 20 men). Two 15-minute ECG recordings with synchronous beat-to-beat blood pressure monitoring were obtained before and 14-17 days after initiation or adjustment of rate control therapy. Mean arterial pressure (MAP), MAP variability (average real variability (ARV), root mean square of successive differences (RMSSD)), the proportion of hemodynamically ineffective beats (HIB; at three relative pulse-pressure thresholds), heart rate (HR), RR variability indices (nRMSSD, CVRR, pNN10%), and the burden of short RR (proportion of RR intervals below an individual RRx threshold) were calculated.

Results. HR decreased from 106,6±12,1 to 85,4±10,5 bpm (p<0,001). The proportion of HIB decreased at all thresholds (mild 26,5±8,4→ 13,5±8,0%, moderate 15,2±8,8 → 6,0±6,8%, severe 6,8±5,4→ 2,4±3,6%; p for all <0,001). MAP remained stable (94,3±11,6 → 93,3±13,7 mm Hg; p=0,67), whereas MAP variability decreased (ARV and RMSSD: p for both <0,001). RR variability parameters increased (nRMSSD, CVRR, pNN10%; all p<0,001), and the burden of short RR fell from 37,5±12,5 to 12,7±9,7% (p<0,001). With β-blocker monotherapy, reductions in mild HIB and short-RR burden were more pronounced, whereas adding digoxin was associated with a greater increase in pNN10%. Despite consistent group-level trends, marked inter-individual differences in response were observed.

Conclusion. Adjustment of rate control therapy in permanent AF is associated with fewer HIBs, lower MAP variability and a reduced burden of short RR intervals without a decrease in mean MAP, thereby improving beat-to-beat hemodynamic metrics while preserving systemic blood pressure. The inter-individual heterogeneity of these effects at similar HRs supports personalized rate control strategies targeting not only average HR but also beat-to-beat hemodynamic parameters and warrants confirmation in larger prospective studies.

This article presents four cases of successful sinus rhythm restoration using cavutilide in patients with characteristics unfavorable for pharmacological cardioversion. The cases include atrial fibrillation and flutter associated with transthyretin amyloidosis, obstructive hypertrophic cardiomyopathy, a long-standing (3 years) persistent arrhythmia, and arrhythmia-induced cardiomyopathy complicated by a significant decrease in cardiac pump function. In all cases, the use of cavutilide in broken doses under QTc interval monitoring resulted in sinus rhythm restoration. The results are compared with data from previously published phase III and post-marketing studies, in which cavutilide demonstrated high efficacy and a favorable safety profile. These studies, however, did not include patients with such severe structural cardiac changes and such prolonged atrial fibrillation. The presented data demonstrate the efficacy and safety of cavutilide in a significantly broader patient population.

This article presents literature data and the results of our own clinical experience demonstrating that atrial fibrillation (AF), a stereotypical clinical manifestation of pathological myocardial fibrosis, can be caused by various, not always obvious, triggers. Morphological and clinical classifications of fibrosis are presented. Multifactorial origin of myocardial fibrosis is substantiated. Pathogenetic mechanisms, mediated by hypoxic damage to cardiomyocyte mitochondria, are described. Emphasis is placed on some non-obvious causes of mitochondrial dysfunction that are widespread in the population and may contribute to AF resistance to antiarrhythmic and interventional treatments. In the vast majority of cases, these etiological factors remain undetected, as they are not included in the algorithms of current guidelines. The authors present their own clinical data on neuromodulation treatment of elderly patients with AF and heart failure, along with a hypothesis for possible myocardial regeneration based on stimulation of endogenous myocardial stem cell differentiation. They also develop an algorithm that, in the author’s opinion, could be useful in supplementing the standard examination of patients with AF to improve long-term treatment effectiveness.

Atrial fibrillation (AF) is the most common supraventricular tachyarrhythmia and is associated with increased cardiovascular complications and mortality. The current patient management paradigm is shifting from a rate control strategy to early and proactive rhythm control, as supported by large randomized trials and current European and Russian guidelines. This review examines the pathophysiological basis of arrhythmogenesis in AF, including the levels of electrical, mechanical, structural, and autonomic atrial remodeling, as well as the key mechanisms of arrhythmia initiation and maintenance (ectopic activity, reentry, trigger activity/delayed afterdepolarizations). Particular attention is paid to the pharmacological strategy of rhythm control using following Vaughan-Williams class I and III antiarrhythmic agents: the molecular targets, pharmacokinetics, clinical efficacy, and safety profile of propafenone, flecainide, lappaconitine hydrobromide (allapinin), ethacizine, amiodarone, sotalol, and others are analyzed, including drugs primarily available in Russia. Based on current data and guidelines, an algorithmic approach to the selection of anti-relapse therapy is proposed, taking into account the patient’s phenotype (paroxysmal or persistent AF, structural myocardial pathology, heart failure coronary artery disease, left ventricular hypertrophy), the level of atrial remodeling, conduction system characteristics, comorbidities, and drug interactions. The characteristics of antiarrhythmic therapy in the early period after cardioversion and after pulmonary vein catheter isolation as part of a hybrid strategy (invasive+drug therapy) are separately discussed. This review is intended for practicing cardiologists and arrhythmologists and aims to facilitate the individualization of antiarrhythmic drug selection within the safe and effective rhythm control strategy for AF.

Interventional treatment remains one of the most effective methods of rhythm control in most patients with atrial fibrillation (AF). The development of innovative methods and the introduction of novel technologies in modern arrhythmology are expanding the potential for maintaining a stable sinus rhythm, reducing the risk of thromboembolic complications, and improving patients’ quality of life. In addition to traditional electrical cardioversion, drug-based approaches, including the use of Russian-made antiarrhythmic agents, are increasingly being used when performing intraoperative cardioversion in patients with AF. This paper presents experience with the use of Refralon (cavutilide) for pharmacological cardioversion in the acute phase of radiofrequency pulmonary vein isolation in patients with various AF forms.

Aim. To compare the effectiveness of cavotricuspid isthmus reablation in patients with typical atrial flutter (AFL) using a standard approach and intracardiac echocardiography (ICE).

Material and methods. The study included 112 patients with recurrent AFL after cavotricuspid isthmus ablation. Patients were divided into two groups based on the ICE performance potential. In the first group, 54 patients underwent ablation using ICE; in the second (control), 58 patients underwent ablation using a standard fluoroscopy technique. ICE allowed us to assess cavotricuspid isthmus structure in patients with recurrent AFL as follows: proximal isthmus >7 mm (35%), Eustachian valve base >7 mm (48%), and a non-uniform central isthmus (13%). Achievement of bidirectional conduction block in the cavotricuspid isthmus was assessed — 52/54 (96,3%) in the ICE group and 52/58 (89,7%) in the control group (P=0,27). The follow-up period was 24 months.

Results. The mean procedure duration was longer in the ICE group (54,0±16,8 min) compared to the control group (46,9±11,9 min). However, the mean fluoroscopy time was significantly shorter in the ICE group — 2,9±1,1 min and 6,3±1,8 min, respectively (P=0,003). AFL recurrence after reablation was detected in 3 (5,8%) patients in the ICE group and in 8 (13,8%) individuals in the control group (P=0,21).

Conclusion. During cavotricuspid isthmus reablation in patients with recurrent typical AFL, isthmus structural characteristics were identified that were likely associated with reduced ablation efficacy. The use of ICE in reablation was associated with a reduction in fluoroscopy time. However, the risk of recurrent AF is equally low with both standard imaging and with ISE.

Catheter-based pulmonary vein isolation is the treatment of choice for patients with symptomatic atrial fibrillation (AF). Despite technological advances, the treatment efficacy, according to various sources, does not exceed 60-80%. In the vast majority of cases, this is due to nonpulmonary sources of arrhythmia. One of the most underestimated structures for the initiation and maintenance of AF is the left atrial appendage (LAA). This literature review provides a current understanding of LAA isolation methods, their effectiveness, and potential complications. It also addresses the issue of potential thromboembolic events after LAA isolation, which is the most common and significant limitation to the widespread use of procedure.

Cryoballoon ablation (CBA), along with radiofrequency ablation and pulsedfield ablation, has proven to be a safe and equally effective method with a short learning curve and minimal time investment. The CBA technique for atrial fibrillation (AF) involves cryoballoon pulmonary vein occlusion, which is confirmed by the absence of contrast leakage from the target vein on fluoroscopy, followed by cryotherapy. Numerous studies have demonstrated the negative impact of fluoroscopy on the human body. This is especially relevant in centers performing a high volume of surgical procedures. This paper presents the immediate and long-term results of non-fluoroscopy CBA of AF and describes the methodology. This technique involves intravascular ultrasound-guided (IVUS) manipulations, eliminating the need for contrast agent or ionizing radiation. It also simultaneously monitors the position of tools within the heart cavities and the echo-free space. The technique is described step by step and illustrated with IVUS screenshots and explanations. Over eight years of clinical experience using non-fluoroscopy CBA of AF has demonstrated that its effectiveness and safety are comparable to the classical technique using fluoroscopy and venography. It eliminates the negative effects of ionizing radiation and radiocontrast agents, maintains the "one shot" principle, does not increase surgical time, and is reproducible.

Interventional treatment of atrial fibrillation, one of the most common arrhythmias, involves various ablation techniques. Their potential has expanded in recent years due to the availability of electromagnetic fields (electroporation) in addition to thermal myocardial procedures (radiofrequency or cryoablation). Surgical treatment of any type is associated with a certain risk of various complications, some of which are more common with traditional techniques, while others are more common with newer ones. The range of possible complications and the extensive research on this topic require further study to better understand the problem and treat patients in clinical practice. This review presents the main types of potential complications associated with atrial fibrillation ablation and analyzes data from recent large studies.

Arrhythmia-induced cardiomyopathy (AiCM) is a reversible complication of atrial fibrillation/flutter, but its diagnosis and optimal management remain challenging clinical issues. Long-term follow-up of patients with AiCM is of particular interest for assessing long-term outcomes and improving management strategies. This article describes a case of a 50-year-old female patient with an aggressive onset of tachystolic atrial fibrillation. This led to severe left ventricular dysfunction, arrhythmogenic shock, and life-threatening complications, including pulmonary embolism and ischemic stroke, despite optimal antithrombotic therapy. Initially, despite pharmacotherapy and multiple electrical cardioversions, stable sinus rhythm could not be achieved. A triple chamber cardioverter-defibrillator was implanted with the expected subsequent atrioventricular junction destruction. However, following rhythmcontrol strategy was further selected: a series of catheter ablations (pulmonary vein isolation and atrial substrate modification) were performed, which restored and maintained sinus rhythm. This resulted in complete normalization of left ventricular function and heart failure compensation over a 10-year period. Ten years after the last ablation, a late arrhythmia recurrence was noted, requiring repeat surgery. This case demonstrates the effectiveness of an active, including multi-stage, rhythm control strategy for AiCM, which can lead to complete and long-term restoration of cardiac function. Key aspects of management include early and aggressive arrhythmia termination, readiness to adjust the strategy, awareness of the risk of late recurrences due to progressive atrial remodeling, and the need for lifelong follow-up.

Currently, catheter-based methods are the leading approach to treating cardiac arrhythmias. A current trend in ablation is the use of navigation mapping, which offers high accuracy in localizing arrhythmias. The aim of this review is to present modern navigation systems and catheters, their characteristics, and potential. The results of studies on the use of high-density mapping for cardiac arrhythmias such as atrial fibrillation, ventricular tachycardia, and atrial tachyarrhythmias are presented, confirming the effectiveness of this approach in real-world practice.