Aim. The aim of the study was to assess the impact of comorbidities and duration of arrhythmic anamnesis on the results of left atrium voltage mapping in patients with persistent atrial fibrillation (AF).
Methods. The study enrolled 50 patients who underwent the first radiofrequency ablation of persistent AF. Left atrium endocardial voltage maps were obtained using a 3D electroanatomical mapping system during AF. The voltage maps consisted of at least 2,000 points, with an average of 2,128±104 points. Low-voltage areas (LVA) were defined as <0.5 mV. The percentage of LVA% and very LVA% were calculated. Results. We found a statistically significant correlation of LVA% with age (p<0.001, r=0.720), female sex (p=0.016), and the duration of arrhythmic history at the time of the start of persistence (p<0.001, r=0.503). Based on the data obtained, an original scale was developed to predict LVA%. The scale includes age, female sex, and the duration of arrhythAim. The aim of the study was to assess the impact of comorbidities and duration of arrhythmic anamnesis on the results of left atrium voltage mapping in patients with persistent atrial fibrillation (AF).
Methods. The study enrolled 50 patients who underwent the first radiofrequency ablation of persistent AF. Left atrium endocardial voltage maps were obtained using a 3D electroanatomical mapping system during AF. The voltage maps consisted of at least 2,000 points, with an average of 2,128±104 points. Low-voltage areas (LVA) were defined as <0.5 mV. The percentage of LVA% and very LVA% were calculated.
Results. We found a statistically significant correlation of LVA% with age (p<0.001, r=0.720), female sex (p=0.016), and the duration of arrhythmic history at the time of the start of persistence (p<0.001, r=0.503). Based on the data obtained, an original scale was developed to predict LVA%. The scale includes age, female sex, and the duration of arrhyth

Aim. To develop a predictive model and a clinical risk score for developing arrhythmia-induced cardiomyopathy (AIC) in children with idiopathic ventricular arrhythmias (VA).
Methods. The study included 492 children aged 1 to 17 years with idiopathic VA. In 392 patients demographic, clinical and diagnostic-related variables were evaluated as potential prognostic factors using binary logistic regression. The scores for each predictor were set based on the odds ratio. Validation of the model was carried out on a test group (n=100).
Results. It was found that body surface area ≥ 1,7 m2 increases the ratio of developing AIC by 4,9 times (1 point), the premature ventricular contraction’s coupling interval < 434 ms. - by 3,7 times (1 point), the burden of VA 25-29% - by 8,4 times (2 points), the burden of VA 30-34% - 11,3 times (3 points), the burden of VA ≥ 35% - 17,2 times (4 points). The specificity of the risk score was determined by the ROC curve. A low probability of developing AIC was determined with a score of up to 2 (specificity <48.1%), an average probability was determined with a score 3-4 (specificity 67.5-81.8%), a high probability was determined with a score 5-6, (specificity >95.1%). The AUC of the predictive scale was 0.805±0.037 (95% CI: 0.732-0.878), p<0.001. The AUC of the of the predictive scale in the test group was 0.893±0.034 (95% CI: 0.827-0.96),p<0.001. The difference in the AUC of the scores in training and test groups was 0.088±0.05. The AUCs were comparable (p=0.078).
Conclusion. In this study we identified independent predictors of IAC in children with idiopathic VA. A clinical risk scale of AIC has been developed based on the obtained predictors. Routine use of the AIC risk scale will lead to personalized monitoring and treatment of each child with idiopathic VA.

Aim. To evaluate the prognostic value of local captures after pulmonary vein isolation in patients with nonparoxysmal atrial fibrillation (AF) for the long-term results of radiofrequency ablation (RFA).
Methods. A single-center observational prospective study. The total number of patients 110. All patients underwent primary catheter ablation for nonparoxysmal AF. During the operation, the activity of pulmonary veins and the presence of local captures were assessed. Patients with local captures in at least one pulmonary vein were included in the first group. Patients who had no local captures were included in the second group. The number of patients in the first group is 54 patients, the number of patients in the second group is 56 patients. The groups had no statistically significant differences in the main indicators -gender, weight, age, duration of medical history, volume of the left atrium and left ventricular ejection fraction, as well as in concomitant pathology. The time of RFA and fluoroscopy, and the duration of operations between the groups also had no statistically significant differences.
Results. The follow-up period was 800 [286.5;800] days. The overall effectiveness of the treatment was 68.2% (75 patients out of 110), considering repeated operations. In the group with local captures, sinus rhythm was maintained at the end of the follow-up period in 42 out of 54 patients (77,7%), in the group without local captures in 33 out of 56 patients (58,9%). The difference is statistically significant (odds ratio 2,439 (95% confidence interval 1,060 -5,615 p=0,034). The presence of local captures in the construction of a multifactorial logistic regression model is a predictor of the effectiveness of RFA (χ2=14,710; p=0,012).
Conclusion. In this study, local captures in the pulmonary veins in patients with nonparoxysmal atrial fibrillation were a predictor of improved long-term results of radiofrequency ablation.

Aim. To study the ablation index (AI) in the context of catheter treatment of ventricular tachycardia (VT) without the use of fluoroscopy in patients with chronic heart failure.
Methods. Catheter ablation of VT was performed in 47 patients with coronary heart disease and chronic heart failure. Intraoperative parameters of the ablation, including the average ablation index, were assessed. The fact of arrhythmia induction after a series of radiofrequency exposures was assessed. Recurrence of VT was also assessed. The observation period was 12 months.
Results. During surgery after ablation exposure, arrhythmia induction was impossible in 100% of patients. After 12 months of observation, freedom from arrhythmia was 84,8%. Patients without recurrence of VT had a statistically significantly higher mean AI (612 [522,5; 683,5]) than with recurrence of VT (7 (15,2%) patients) (438 [416,5; 462]) (p=0,001). The possibility of predicting recurrence of VT depending on the mean AI value was also assessed. It was found that with the mean AI value greater than or equal to 473, the risk of recurrence of VT is lower (p=0,001).
Conclusions. AI can be used as a parameter for monitoring effective ablation exposure in the context of catheter ablation of VT along with other determinants currently used.

Aim. To compare immediate and long-term outcomes of catheter-based atrial fibrillation (AF) treatment following pulmonary vein (PV) cryoballoon ablation (CBA) using the second-generation cryoballoon and PV radiofrequency ablation (RFA) performed on the navigation system using the contact force-sensing catheter with the AI module.
Methods. The study included 199 patients referred for PV isolation between 2018 and 2021. Patients were divided into two groups: the study group (n=110) underwent PV isolation via RFA using the catheter with the AI module; the control group (n=89) underwent PV CBA using the second-generation cryoballoon. The follow-up period was limited to 36 months, with a mean follow-up of 27.9 ± 14.2 months.
Results. The three-year efficacy of CBA and RFA using the AI module was comparable (freedom from atrial tachy­ arrhythmias: RFA group 0.61±0.05, CBA group 0.62±0.05 (Log-Rank test, p = 0.896)), with similar complication rates and profiles (3.6% (n=4) vs. 4.5% (n=4), p=0.759). The AF recurrence rate during the blanking period was significantly lower in the RFA group using the AI module (1.8% (n=2) vs. 9.0% (n=8) in the CBA group, p=0.045). Procedure duration was significantly shorter in the cryoablation group (RFA 92.7±20.9 min, CBA 83.9±19.6 min, p=0.005). The need for repeat intervention was comparable between groups (RFA 21.8% (n=24), CBA 30.3% (n=27), p=0.171).
Conclusion. Comparative analysis of the three-year efficacy of radiofrequency antral pulmonary vein isolation using the catheter with the “Ablation Index” (AI) module demonstrated results comparable to ablation with the secondgeneration cryoballoon. Furthermore, during the blanking period, the RFA group showed a statistically significant reduction in AF recurrence compared to the CBA group.

Aim. To evaluate the effect of atrial pacing (AP) on the development of atrial extrasystoles and episodes of supraventricular tachycardia in patients with dual-chamber cardiac pacemakers.
Methods. The study included 97 patients who underwent implantation of dual-chamber cardiac pacemakers. The analysis of 169 control examinations in the period from 1 to 20 months after surgery was carried out. The parameters of atrial stimulation, group atrial extrasystoles, and episodes of supraventricular tachycardia were evaluated. The initial data was processed in Microsoft Excel and Access, statistical analysis was performed in Jupyter Notebook (Python 3.x).
Results. A moderate positive correlation was established between atrial extrasystoles and episodes of supraventricular tachycardia (p=0.623, p <0.001). In the AP group ≥ 91%, there was a decrease in the frequency of AT/AF >24 hours (p = 0.060). Logistic regression showed a significant reduction in the risk of AT/AF >24 hours with AP 51 - 90% (odds ratio 0.31, p=0.002).
Conclusion. High level of atrial stimulation may reduce the risk of prolonged episodes of supraventricular tachycardia, however, the effect of atrial stimulation of cardiac pacemaker on episodes of atrial extrasystoles has not reached statistical significance.

A clinical case of a child with a rare mitochondrial disease, Kearns-Sayre syndrome, who had a pacemaker implanted due to the development of complete atrioventricular block, is presented for the first time in the Republic of Kazakhstan. The issues of complex diagnostics and management tactics are discussed.

The article focuses on the analysis of device selection for cardiac resynchronization therapy based on the stratification of sudden cardiac death risk. Various diagnostic methods and clinical-anamnestic data are considered, along with their role in predicting arrhythmogenic events and making implantation decisions. Differences in implantation approaches for patients with ischemic and non-ischemic cardiomyopathy are discussed, emphasizing the importance of a combined risk assessment and the use of prognostic models. Unresolved issues related to optimal patient selection, timing for evaluating CRT effectiveness, and potential implantation strategies considering both economic and clinical factors are also reviewed.

The article presents modern methods of anesthetic aids used in the case of such interventional and surgical interventions as implantation of a pacemaker, cardiac resynchronization therapy, cardioverter defibrillator and catheter ablation. The advantages, disadvantages and problematic issues of anesthesia are discussed depending on the type of intervention and the patient’s condition. Based on the analyzed data, it is concluded that anesthesia during interventions in patients with arrhythmological profile is a global practice and emphasizes the positive impact of anesthesia methods on the quality and safety of procedures performed.

Among studies addressing ECG-based risk stratification for sudden cardiac death and life-threatening ventricular arrhythmias, novel approaches to ECG data analysis and derived markers of myocardial electrical instability are of particular interest. Notably, metrics obtained through vector-based, frequency-domain, and nonlinear ECG analysis have demonstrated significant value as predictors of high-risk ventricular arrhythmias and sudden cardiac death.