Aim. To assess the relationship between structural and functional parameters of the heart and the presence and prevalence of low-amplitude activity (LAA) zones according to high-density voltage mapping of the left atrium (LA) in patients with atrial fibrillation (AF).

Methods. The study included 57 patients (23 women and 34 men) 55.4±9.8 years with paroxysmal (n=40, 70%) and persistent AF (n=17, 30%). Transthoracic echocardiography, assessment of deformation of both atria - 2D Strain STE were performed in all patients. High-density voltage mapping of the LA was performed intraoperatively before the catheter ablation procedure.

Results. LAA zones were registered in 33% of patients. Persistent form of AF, LA stiffness index, reservoir and contractile functions of the LA, E/A and E/e’ ratios became the strongest predictors of identifying LAA zones in the LA. A prognostic model was constructed using the LA stiffness index and E/A ratio, which determines a high probability of identifying LAA zones in the LA with a sensitivity and specificity of 74 and 74%, respectively.

Conclusion. Preoperative assessment of the stiffness index, reservoir and contractile function of the LA, E/A and E/e’ ratios has predictive value in assessing the prevalence of fibrosis using high-density voltage mapping of the LA. Studying of noninvasive ultrasound parameters in combination with known predictors of effectiveness will allow us to create algorithms for selecting patient selection for catheter ablation and avoid predictably ineffective interventions.

Aim. To identify predictors of atrial tachyarrhythmias inducibility after pulmonary vein isolation in patients with paroxysmal atrial fibrillation (AF).

Methods. The study included 82 patients (63,65±9,21 years, 45 men (54,9%)) with paroxysmal AF referred for primary radiofrequency ablation. All patients underwent voltage mapping of the left atrium, with areas exhibiting bipolar signal amplitudes less than 0.5 mV identified as low-voltage areas (LVA). After pulmonary vein isolation, arrhythmia induction was performed by pacing with a cycle length of 180 milliseconds sequentially from the left atrial appendage, anterior wall, roof, posterior wall, and mitral isthmus area. When sustained tachycardia was induced, electrophysiological mapping of the left atrium was performed to verify the tachycardia mechanism.

Results. Tachyarrhythmias were not induced in 25 patients (30,48%), while 57 patients experienced induced tachyarrhythmias of varying durations (69,52%). The arrhythmia mechanisms in patients with induced sustained tachycardias were macro re-entry in 12 cases (38,7%), atrial fibrillation in 12 cases (38,7%), and a combination of macro re-entry and atrial fibrillation in 7 cases (22,6%). We found a statistically significant correlation between the induction of any type of arrhythmia and body mass index (p=0.014) and left atrial volume (p=0.024). A correlation was also found between AF induction and left atrial volume (p=0.016) and the percentage of LVA (p=0.014). The threshold value of the percentage of LVA indicating the probability of AF induction was 2.2%. No correlation was found between macro re-entry induction and any of the investigated factors.

Conclusions. Independent predictors of sustained arrhythmia induction were left atrial volume and body mass index. Atrial fibrillation induction was associated with left atrial volume and LVA percentage with a threshold of ≥2.2%. No significant associations with the investigated parameters were found for macro re-entry.

Aim. To evaluate the impact of Marshall ligament cutting off on the incidence of atrial fibrillation (AF) within 1 month after coronary artery bypass grafting (CABG).

Methods. A double-blind, randomized, single-center clinical trial included 60 patients; 30 patients were allocated to the Marshall ligament cutting off group (main group), and 30 patients to the group without Marshall ligament cutting off (control group). The groups did not differ in baseline clinical and demographic parameters. The primary endpoint was the occurrence of AF within 28 days after CABG. Logistic regression was performed to identify efficacy factors.

Results. Postoperative AF developed in 9 patients: 7 patients in the control group and 2 patients in the main group. The statistical model revealed two independent factors that significantly reduced the risk of postoperative AF: performing the surgery without cardiopulmonary bypass (off-pump) and Marshall ligament cutting off (p=0.030 and p=0.048, respectively). The logistic regression model demonstrated excellent predictive ability and high patient classification accuracy; sensitivity was 93.8%, specificity was 62.5% at a cutoff of 0.5. The area under the ROC curve (AUC=0.898) indicates the model’s excellent ability to distinguish between patients with and without postoperative atrial fibrillation.

Conclusion. Marshall ligament transection during off-pump CABG prevents the development of postoperative atrial fibrillation.

Aim. To evaluate survival outcomes, the frequency of adverse events and repeat interventions, and to identify predictors of adverse outcomes in patients with chronic heart failure (CHF) with improved left ventricular ejection fraction (LVEF) receiving implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) for primary prevention of sudden cardiac death (SCD).

Methods. A single-center retrospective study was conducted including 87 patients with CHF and improved LVEF (baseline LVEF ≤35%, LVEF ≥40% at enrollment with absolute increase ≥10%), who underwent ICD (n=34; 39.1%) or CRT-D (n=53; 60.9%) implantation at the Almazov National Medical Research Centre, Ministry of Health of Russia between 2016 and 2022. The primary endpoint was all-cause mortality; secondary endpoints included episodes of inappropriate electrical therapy and complications related to implanted devices. The median follow-up period after enrollment was 5.2±2.8 years. Statistical analysis was performed using StatTech v. 4.8.5 software.

Results. During the follow-up period, 10 deaths (11.9%) were registered: 4 cases among ICD patients (11.8%) and 6 cases among CRT-D patients (12.0%) with no statistically significant differences between groups. The overall rate of device-related complications was 16.1%, with the highest incidence of lead dislodgement (6.9%) and lead damage (4.6%). Inappropriate electrical therapy was registered in 13.8% of patients. Risk factors associated with unfavorable prognosis were identified: ischemic etiology of CHF, valvular heart disease, incomplete recovery of left ventricular systolic function, and atrial fibrillation.

Conclusion. The presence of ICD/CRT-D in patients with CHF and improved LVEF is associated with substantial risks of complications and inappropriate therapy, indicating the need for improvement of personalized approaches to primary SCD prevention in this patient category.

Aim. Cardioneuroablation (CNA) is an emerging therapeutic approach for functional bradyarrhythmias, yet the dynamics of electrophysiological (EP) parameters following the procedure remain insufficiently characterized. Stratifying patients according to the type of conduction disturbance may provide a more precise assessment of procedural outcomes.

Methods. This prospective single-center study included 109 patients (38.2±11.4 years; 61% male) with symptomatic functional bradyarrhythmias who underwent CNA using anatomical and/or electroanatomical mapping-guided strategies. Heart rate (HR), sinus node recovery time (SNRT), corrected SNRT (cSNRT), AH, PQ, and HV intervals, atrioventricular node effective refractory period (ERP AV), and Wenckebach point were measured before and after CNA. Patients were stratified into three groups: sinus node dysfunction (SND, n=46), atrioventricular node dysfunction (AVND, n=41), and combined phenotype (SND+AVND, n=22).

Results. CNA resulted in a significant increase in HR (from 61 [53-70] to 72 [64-80] bpm, p<0.001), reduction of SNRT (from 1375 [1169-1770] to 1190 [1000-1400] ms, p<0.001) and cSNRT (from 367 [258-512] to 280 [209-368] ms, p<0.001), as well as shortening of AH interval (from 108 [86-166] to 96 [84-118] ms, p=0.001) and PQ interval (from 186 [160-220] to 169 [150-200] ms, p<0.001). In the SND group the most pronounced changes were observed in HR and SNRT, while in the AVND group the greatest effect was noted in AH and PQ intervals. The combined phenotype demonstrated mixed effects.

Conclusion. CNA induces significant modifications in EP parameters, reflecting attenuation of vagal influence on the cardiac conduction system. The magnitude and profile of these changes depend on the underlying conduction phenotype, underscoring the importance of personalized stratification in the evaluation of procedural efficacy.

Aim. To study the functional state of the left heart chambers during short-term stimulation of the His bundle, the interventricular septum and the apex of the right ventricle (RV) during diagnostic intracardiac electrophysiological study (EPS).

Methods. The study included 5 patients who underwent intracardiac EPS for supraventricular tachyarrhythmias, which included an experimental program of short-term stimulation from various anatomical zones of the RV (His bundle, interventricular septum, apex of the right ventricular) with additional registration of parameters of the left heart chambers’s functional state in the sinus rhythm. A comprehensive assessment of hemodynamic parameters was performed: global longitudinal strain (GLS) and postsystolic index (PSI) of the left ventricle (LV), E/e’, volume of the left atrium (VLA) and strain of the left atrium (LA) in the reservoir phase. The initial data was processed in Microsoft Excel, and statistical analysis was performed using Statistica 10.0 (StatSoft Inc.) and Python (SciPy, Seaborn, Pandas libraries).

Results. All the parameters under consideration differ significantly between the stimulation modes (in all cases p<0.01). The most pronounced changes are observed with apical RV stimulation: patients have worse LV GLS and LA strain values, as well as the highest VLA compared to sinus rhythm and His bundle stimulation. In contrast, with His bundle stimulation, the GLS, VLA, and LA strain values are close to those in sinus rhythm, indicating a more physiological contraction of the heart in this mode. Significant correlations were established between PSI and E/e’ (r=+1.0), PSI and LA strain (r=-1.0), as well as E/e’ and VLA (r=+1.0) during electrical stimulation of various anatomical zones, which confirms the relationship between dissynchrony, diastolic function and LA overload.

Conclusion. The worst values of LV GLS and LA strain, as well as the highest LAV, were observed with apical stimulation of the RV, while with stimulation of the His bundle, the values of GLS, VLA and LA strain are close to those with sinus rhythm, which indicates a more physiological contraction of the heart in this mode.

Aim. The aim of the study was to study the effect of first appeared persistent left bundle branch block on the prognosis of patients after «MedLab-CT» transcatheter aortic valve implantation (TAVI) in the middle long-term follow-up period.

Methods. The study included 129 patients after the TAVI procedure, who initially did not have LBBB. The average age of patients was 70.2±5.2 years, body mass index - 31.4±5.9 kg/m2, the proportion of men was 36%, arterial hypertension was diagnosed in 93%, diabetes mellitus in 32%, coronary heart disease in 59% of patients, paroxysmal form of atrial fibrillation was registered in 16%, permanent form of atrial fibrillation - in 3% of patients. According to echocardiography the end-diastolic volume was 107.7±30.9 ml, the ejection fraction was 61.4±10.4%, the maximum and average pressure gradient on the aortic valve was 91.7±25.7 mmHg and 52.7±16.4 mmHg respectively. The width of the QRS complex was 84.1±12ms. Depending on the occurrence of LBBB after the TAVI procedure, the patients were divided into 2 groups: the first group included 98 patients without LBBB (the width of the QRS complex was 98.4±16ms), the second included 31 patients with LBBB (the width of the QRS complex was 149.6±17ms). The groups were comparable in other clinical, demographic and ultrasound parameters. The follow-up period was 60 months.

Results. There were no differences in echocardiography data in both groups, and mortality rates from all causes were also comparable. During the follow-up period in the LBBB group two patients was implanted a pacemaker (6.45%; p=0.001). The LBBB after TAVI did not increase all-cause mortality in patients (OR 1.084; DI= 0.353-3.209; p=0.912).

Conclusion. The first time arisen LBBB does not increase mortality in patients after TAVI «MedLab-CT» in the middle long-term follow-up period, but it is associated with a higher risk of developing a high-grade atrioventricular block requiring pacemaker implantation.

Aim. To evaluate the effectiveness and safety of the use of the irreversible electroporation system for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF).

Methods. The study included 25 patients with AF: 20 with paroxysmal (80%) and 5 with persistent (20%) forms. Among the participants, there were 16 men (64%), an average age of 58±9 years. All patients underwent PVI using pulsed field ablation (PFA), which leads to irreversible electroporation. Two patients (8%) underwent isolation of the cavotricuspid isthmus using PFA. To assess the safety of the procedure, laboratory diagnostics were performed to evaluate free hemoglobin and troponin I, and magnetic resonance imaging of the brain was performed before and after the procedure. In 3 months after procedure all patients underwent multi-electrode mapping of the left atrium and pulmonary veins to assess the PVI, and, if necessary, additional isolation using radiofrequency ablation. The follow-up period was 12 months.

Results. PVI was achieved in 100% of cases. Isolation of the cavotricuspid isthmus before achieving a bidirectional block of conduction was successfully performed also with the same energy source. Among the complications, there was only 1 case related to vascular access. The average duration of the PFA catheter in the left atrium was 21.9±11.7 minutes, and the average fluoroscopy time was 11:23±5:41 min:sec. According to the results of repeated multi-electrode mapping, all pulmonary veins remained isolated in 22 patients (88%). After 12 months of follow-up, 19% (76%) of patients still had a sinus rhythm.

Conclusion. Thus, the new national technology of irreversible electroporation has demonstrated its effectiveness and safety, comparable to traditional thermal techniques for pulmonary vein isolation in patients with AF.

We presented 2 clinical cases for patients with Long QT3, where we used flecainide together with beta-blocker therapy the first time in the Russian Federation in this disease.

Despite effective prevention of sudden cardiac death in patients with structural heart disease, reducing the burden of ventricular arrhythmias remains a significant clinical challenge. The limited efficacy and potential side effects of antiarrhythmic therapy increase interest in interventional treatment for ventricular tachycardia (VT), which has evolved considerably from open-heart surgery to modern catheter-based techniques. The optimal place for catheter ablation of substrate-related VT and the most effective approaches for these procedures have yet to be established. A thorough understanding of the gaps in evidence, as well as the possibilities and limitations of catheter ablation, is essential for the effective management of patients with structural heart disease-related VT.

The results of an analysis of Holter electrocardiogram monitoring data from an asymptomatic female patient with a pattern of intermittent Wolff-Parkinson-White (WPW) phenomenon and unusual QRS morphology, with a QRS duration reaching 190 ms are presented. The clinical significance of such marked QRS widening, as well as approaches to determining therapeutic management, are discussed.