Aim. To evaluate the association of computed tomography measurements (volume and density) of epicardial adipose tissue (EAT) with the blood concentration of adipokines, proinflammatory cytokines and catecholamines in patients with atrial fibrillation (AF).

Methods. We included 32 patients (median age 58.5 (52.5; 64.0); 18 men) with AF scheduled for radiofrequency ablation. All patients underwent multispiral computed tomographic coronary angiography and segmentation of the EAT. In addition, the concentration of adiponectin, leptin, resistin, interleukins 1b, 6, 8 and methanephrine in the blood was determined by enzyme immunoassay.

Results. А negative correlation was established between the volume and the density of EAT (r= - 0.5, p<0.05). The X-ray density of EAT negatively correlated with the concentration of methanephrine (r= -0.4) and leptin (r= -0.4), and positively correlated with the concentration of interleukin-8 (r=0.36). In addition, the duration of AF was negatively correlated with the density of EAT (r=-0.42, p<0.05) and positively correlated with the concentration of blood methanephrine (r=0.34, p<0.05). No associations were found between the volume of EAT and the studied blood biomarkers.

Conclusion. The results of the study showed an association between EAT X-ray density and the concentration of leptin, interleukin-8 and metanephrine in AF patients.

Aim. This study aimed at investigating the safety of out-of-hospital initiation of flecainide in patients presenting with atrial or ventricular arrhythmias and structurally normal heart.

Methods. Patients were followed 1 week, 1 month and 2 months after drug initiation either in person or through phone interviews and were asked to report symptoms suggestive of sustained arrhythmia, syncope, aborted sudden death and/or emergency room (ER) visits. QRS duration and QTc intervals were measured in a 12-lead ECG at each follow up. Patients were asked to fill out a treatment satisfaction questionnaire for medication (TSQM), four weeks after drug initiation.

Results. The mean patient age was 48.5 ± 15.7 years, 36 patients (52%) were females. The most frequent presenting arrhythmia was premature ventricular contractions in 34 (45.3%) patients followed by paroxysmal atrial fibrillation in 22 (29.3%) patients. There was a significant increase in the mean QRS duration (89.9 ± 6.8 msec vs 91.1±7 msec, P <0.001) and the mean QTc interval (417.4 ±10.6 msec vs 418 ± 10.4 msec, P = 0.025) at 1 week compared to baseline. Only one patient (1.3%) had a clinically significant (more than 25%) increase in the QRS duration requiring drug discontinuation. There was no reported life-threatening ventricular arrhythmia, syncope, ER visits or aborted sudden cardiac death. There was 6.7% incidence of cardiac adverse events including conduction system abnormalities and atrial flutter, 4% of patients experienced non-resolving extracardiac manifestations. The overall drug discontinuation rate was 10.7%. The mean TSQM score for effectiveness domain was 70.4 ± 23.8 while the mean of the side effects domain was 94.3 ± 14.6, that of convenience domain was 65.2 ± 10.5 and that of global satisfaction was 72.8 ± 21.8.

Conclusion. Out-of-hospital initiation of flecainide is safe and thus feasible, there was no reported documented or suspected life-threatening ventricular arrhythmias. Cardiac and extracardiac adverse events requiring drug discontinuation was effectively detected through clinical and ECG outpatient follow up.

Aim. To compare the frequency and timing of cardiac arrhythmia detection and conduct a clinical and economic analysis of remote telemetry (RT) in elderly and senile patients following dual-chamber pacemaker (PM) implantation compared to in-person clinical follow-up over a 12-month period.

Methods. A prospective study was conducted involving 92 patients (50% female), with a mean age of 71,5 years. The intervention group (n=39) was monitored remotely using the Medtronic CareLink Network, USA, with patients transmitting data monthly for one year. The control group (n=53) underwent in-person clinical follow-ups at one month and one year post-implantation. The groups were comparable in age, sex, clinical diagnoses, and complications (p>0,05). A cost-effectiveness analysis (CEA) was performed, and the cost-effectiveness ratio (CER) was calculated.

Results. No statistically significant differences were observed between the experimental and control groups in the frequency of cardiac arrhythmias. However, significant differences were found in the timing of arrhythmia detection (p<0,001), with earlier detection in the experimental group. According to the results of the clinical and economic costeffectiveness analysis, the CER value for the remote monitoring method (33226,30 [33226,30; 33226,30]) is statistically significantly lower than the similar coefficient for in-person diagnostics (373542,00 [3735,42; 373542,00]).

Conclusion. The use of RT in elderly and senile patients following dual-chamber PM implantation did not show a statistical difference in arrhythmia detection rates. However, cardiac arrhythmias were diagnosed earlier in the experi­ mental group. The cost-effectiveness analysis demonstrated that RT requires lower financial costs to achieve a unit of effectiveness compared to in-person monitoring.

Aim. Atrial fibrillation (AF) represents one of the most critical cardiac arrhythmias, as it significantly increases the risk of stroke. Its detection is particularly challenging due to the unpredictable nature of its episodes.

Methods. This study proposes a low-complexity algorithm, enabling integration into embedded devices for realtime AF episode detection. The proposed method integrates non-linear, time-domain and frequency-domain features extracted from electrocardiogram signals with The LightGBM algorithm (an extension of decision tree algorithm) is used to classify and detect AF.

Results. The model was trained using the MIT-BIH AF Database (MIT-AFDB), achieving sensitivity (Se), specificity (Sp), accuracy rates (Acc), precision (PPV), F1-score and AUC of 0.9838, 0.9690, 0.9748, 0.9543, 0.9688 and 0.9957, respectively. We also performed 10‑fold cross‑validation on this dataset. The obtained values for Se, Sp, Acc, PPV, F1-score, and AUC were, respectively, 0.9837 ± 0.0020, 0.9701 ± 0.0021, 0.9755 ± 0.0007, 0.9559 ± 0.0029, 0.9696 ± 0.0008, and 0.9959 ± 0.0002. This indicates that the model achieves good performance compared to current studies in AF recognition and detection.

Conclusions. The experimental results demonstrate that the model achieves high performance in the classification and detection of AF episodes. Furthermore, the model is suitable for integration into real-time arrhythmia detection systems.

Aim. To study the causal relationship between the functioning of accessory pathway and changes in intraventricular hemodynamics in patients with dissynchronous cardiomyopathy.

Methods. The study included 83 patients with registered preexitation according to ECG data. Patients were divided into study and control group. The study group included 33 patients with diagnosed echocardiographic signs of dissynchronous cardiomyopathy (reduced ejection fraction (EF), increased chamber volume and/or decreased global longitudinal strain (GLS) of the left ventricle (LV)). The control group included 50 patients with Wolff-Parkinson-White syndrome/ phenomenon without dissynchrony.

Results. After radiofrequency ablation (RFA), patients in the study group showed natural normalization of the QRS complex width and LV GLS. The median QRS width before RFA was 110 ms [100; 120] and after RFA 70 ms [60; 80] (p<0.0001). The median LV GLS before RFA was -18.2% [-19.1; -17] and after RFA -21.3% [-23; -19.2] (p<0.0001). Despite the absence of statistically significant differences in the QRS width in patients in the study and control groups, statistically significant differences in the size and LV EF were revealed. In the study group, the median of end-diastolic volume (EDV) of LV (as a percentage of the parameter from the individual predicted norm) was 112% [102; 123] and EF was 64% [55; 65], and in patients from the control group 102% [97; 112] and 65% [64; 66], respectively. The level of significance of the differences for EDV was p=0.0183, for EF it was p=0.0003.

Conclusion. Risk factors of dissynchronous cardiomyopathy (age of patients, right-sided localization of accessory pathway, severity of ventricular preexcitation) are probably of important clinical significance, but are not specific.

Aim. To investigate clinical manifestations, phenotypic variants, genetic features, and outcomes in children with arrhythmogenic cardiomyopathy (ACM).

Methods. The study group consisted of 24 patients (< 18 years of age) with ACM, who were under observation from 2011 to 2024. The median age at ACM diagnosis was 13 years [12-15]. The following data were analyzed: complaints and medical history, laboratory parameters (biochemical markers of inflammation and serum myocardial damage mar­ kers, NT-proBNP levels), electrocardiogram, Holter monitoring, echocardiography results, cardiac magnetic resonance imaging, selective coronary angiography, histological and molecular genetic studies. The median follow-up duration for ACM patients was 27 months [16.5-38].

Results. All patients were unrelated probands. All children presented with asymptomatic ventricular arrhythmias (VA) as the initial manifestation of the disease, 23 (95.8%) patients had complaints: palpitations in 21 (87.5%) children, syncope in 14 (58.3%) children, heart failure symptoms in 12 (50.0%), and isolated chest pain in 4 (16.7%) patients. 5 (20.8%) children had a “hot” phase. Analysis of arrhythmic data revealed several features of ACM in childhood: VAs were polymorphic, daily VA density was less than 20% at the time of diagnosis, presence of late ventricular potentials in most patients, and several criteria from the «repolarization abnormalities» group had low informativeness. During follow-up, 9 (37.5%) children had the right-dominant ACM, 7 (29.9%) had ACM with left ventricle involvement, and 8 (33.3%) had biventricular form. Desmosomal mutations were found in 16 children (66.7%), non-desmosomal gene variants in 8 patients (33.3%).

Conclusion. It has been shown that ACM can manifest at an early age and is associated with the development of arrhythmic events and/or severe heart failure. Increasing awareness among physicians about the early onset of ACM is crucial for timely treatment of heart failure, prevention of sudden cardiac death, and family screening.

Aim. To conduct a comparative analysis of clinical, instrumental, and laboratory diagnostic methods and to identify factors determining the likelihood of sustained paroxysmal ventricular tachyarrhythmias (VT) in patients with indications for cardiac resynchronization therapy (CRT).

Methods. The study included 124 patients with chronic heart failure (CHF) and an implanted CRT-D system. The median age was 58 (52-63) years. Patients were followed for 24 months. Clinical and demographic characteristics, electrocardiographic data, speckle-tracking echocardiographic parameters, and blood biomarker levels were assessed. The primary endpoint was the occurrence of sustained VT episodes recorded by the implanted device. A multivariate logistic regression model was developed to predict the two-year probability of VT occurrence.

Results. During the follow-up period, 29 patients (23.3%) experienced episodes of sustained VT. Univariate analysis identified seven candidate predictors with the highest potential for reaching the endpoint. These included: clinical factors (presence of coronary artery disease and atrial fibrillation); ECG parameters (modified QRS index >0.6, presence of left bundle branch block (LBBB) according to Strauss criteria); echocardiographic findings (global longitudinal strain ≥ -6%, mitral regurgitation of grade 2 or higher); and laboratory markers (galectin-3 ≥ 12 ng/mL). Based on these variables, a predictive model was developed using binary logistic regression to estimate the two-year risk of VT in patients with CRT indications. The Strauss LBBB criterion, although statistically significant in univariate analysis, was not included in the final model. At a regression function cut-off value of 0.228, the model demonstrated a diagnostic accuracy of 73.6% (sensitivity - 86.2%, specificity - 69.6%). The area under the ROC curve was 0.779, which, according to expert grading, indicates good model performance.

Conclusion. The study identified several independent predictors of sudden cardiac death risk in patients with implanted CRT-D devices and enabled the construction of a multifactorial prognostic model. The findings suggest the potential for developing a personalized algorithm for device selection.

The review article discusses current aspects of diagnostics of hereditary arrhythmic syndromes, according to clinical guidelines, and difficulties that have arisen in real clinical practice, as well as possible ways to solve them. A systemic and multidisciplinary approach to solving these problems will contribute to increasing the effectiveness of clinical genetic studies and thereby improving the prevention of malignant arrhythmias and sudden cardiac death.

Clinical observations of the possibility of using the thrombodynamics test (TD) in comparison with standard hemostasis tests in patients with non-valvular atrial fibrillation (AF) and detected thrombosis of the left atrial appendage against the background constant oral anticoagulants are presented. It has been shown that the transfer from one direct oral anticoagulant (DOACs) to another (with a different mechanism of action), as well as from DOACs to warfarin, can change the state of the blood plasma coagulation system towards both hyper- and hypocoagulation. Unlike standard hemostasis tests, TD can be used to assess the prothrombotic status of a patient with AF and personalized selection of effective anticoagulant therapy.

Left bundle branch (LBB) pacing is a novel method of cardiac pacing, which can prevent development of interventricular dyssynchrony, and also could be used as a resynchronization therapy in patients with low ejection fraction and LBB block. Demonstration of the specific electrocardiographic criteria is essential to confirm LBB capture.