Aim. To evaluate the effect of radiofrequency ablation (RFA) of accessory pathways on left ventricle (LV) function in patients with Wolff-Parkinson-White (WPW) syndrome and preexitation-induced dyssynchrony cardiomyopathy.

Methods. The study included 22 patients with registered preexitation on the ECG and signs of dyssynchronous cardiomyopathy according to echocardiography (Echo): asynchronous movement of interventricular septum, ejection fraction (EF) decrease and/or global longitudinal strain of the left ventricle (GLS LV), heart chamber increase. The average age of patients at the time of RFA of the accessory pathways - 11 years [8;14].

Results. A regular normalization of the QRS complex width was observed after RFA (p = 0.0002). To assess reverse LV remodeling, all patients underwent Echo on day 3 after RFA. In patients with an initially reduced LVEF, its increase was noted. In patients with initial dilatation and an increase in LV volume, normalization of these indicators was noted. However, dynamics of LVEF and its volume was not statistically significant in the early postoperative period. According to Speckle-tracking Echo during medical check-up, complete normalization of longitudinal deformation was observed in 13 patients (59%), this indicator improvement - in 7 patients (31.8%). The average GLS LV before RFA was -17.25 [-16.4; -19], after RFA - -21.5 [-19; -24] (p = 0.0001).

Conclusion. Reverse remodeling and restoration of LV function after RFA of accessory pathways indicates a cause- and-effect relationship between the accessory pathways functioning and dyssynchronous cardiomyopathy development. Therefore, patients with signs of preexitation-induced dyssynchronous cardiomyopathy are indicated for RFA of accessory pathways, regardless of age and tachycardia paroxysms.

Aim. To evaluate the survival and dynamics of clinical and instrumental data in patients with chronic heart failure (CHF), atrial fibrillation (AF) and cardiac contractility modulation (CCM).

Methods. There were included 54 patients (40 men, median age 59.7 [56.6; 63.9] years) with signs of CHF II (n=27, 50%) functional class and III (n=27, 50%) NYHA functional class, significantly decreased left ventricular ejection fraction (LVEF=30 [24,7; 35,5]%), LV dilatation and paroxysmal (n=27, 50%) or permanent (n=27, 50%) AF. In all patients, devices for CCM were implanted. The dynamics of clinical and instrumental parameters were assessed in 2, 6, 12 and 24 months after implantation. The actual survival patients with CCM was compared with the predicted survival calculated using the Seattle model of heart failure and MAGGIC risk score.

Results. In 14 (28%) of patients CCM resulted in significantly increased clinical, echocardiographic parameters (increase in LVEF by 15 [11; 20]%, decrease in end-systolic volume by 68,5[37.5;104.5] ml and end-diastolic volume by 44 [30,100] мл), increase in walking distance during 6-minute walking test and decrease of NT-proBNP. The only factor significant for maximal response was non-ischemic etiology of CHF (χ²=4.54, p=0.034). During 2 years 21 (42%) patients died. The all-cause mortality in patients with CCM to the first year of observation was 16%, two-year all-cause mortality - 40%. These figures turned out to be significantly higher than predicted according to the Seattle model (χ²=10.93, p=0.001). The predicted and actual risk of death at 12-month follow-up turned out to be comparable when assessing survival parameters according to the MAGGIC scale. (χ²=2.24, p=0.134).

Conclusion. CCM therapy in some patients with CHF of non-ischemic etiology can lead to an improvement of all clinical and instrumental characteristics. At the same time, there is no effect of CCM on the prognosis of patients with CHF. This fact may suggest the need of additional studies with increased number of cases.

Aim. To identify noninvasive markers of atrial electrical dysfunction and risk of nonvalvular atrial fibrillation (AF) and to develop a predictive mathematical model to estimate the AF risk based on electrocardiographic (ECG) P-wave parameters during sinus rhythm.

Methods. The study included 211 patients with cardiovascular pathology (aged median 62 [52; 71] years, 67.8% male, NYHA heart failure class I-III). All patients (follow-up median 45 [26; 67] months) underwent a complex of studies: 12-lead ECG, echocardiography, 24-hour ECG monitoring. Based on surface ECG data during sinus rhythm, parameters of atrial electrical activation were assessed such as Morphology, Voltage and P waves duration (MVP) according to integral analysis by MVP score.

Results. During 3.7-year period, 44 (20.8%) patients experienced new-onset sustained AF and 12 (5.69%) patients developed ischemic stroke. As a result of ROC analysis and univariate Cox regression, independent predictors of AF were identified: P-wave prolongation in the DII lead, 3rd degree or advanced interatrial block (aIAB), an increase P-wave terminal force in lead V₁ (PTFV₁), low-voltage P-wave in the DI lead and сalculated level of abnormal P-wave ≥3 points on the MVP score. Data from multivariate Cox proportional hazards regression analysis confirmed the prognostic significance for three independent predictors of AF: aIAB (hazard ratio (HR) 5.92; 95% confidence interval (CI) [2.48-4.12]; p=0.0001); PTFV₁ (HR 1.14; 95% CI [1.04-1.24], p=0.003); low-voltage P-wave in lead DI <0.1 mV (HR 1.03; 95% CI [1.02-1.05]; p=0.0001); and as a result a mathematical model was created to predict AF risk (-2LL =258; χ²=105; p=0.0001). Predictors such as PTFV₁ (HR 1.41; 95% CI [1.17-1.72], p=0.0001) and MVP score of abnormal P-waves (HR 1.85; 95% CI [1.27-1.72] 2.70], p=0.001) were associated with a high risk of stroke according to Cox regression model (-2LL= 62.5; χ²=38.4; p <0.001).

Conclusion. Complex of ECG markers of atrial electrical dysfunction such as aIAB, PTFV₁, level MVP score of abnormal P-wave and low P-wave voltage allows identifying patients at high risk of AF and ischemic stroke.

Aim. To examine the impact of late gadolinium enhancement (LGE) in the left ventricular myocardium on magnetic resonance imaging (MRI) on overall mortality and the phases of arrhythmic events in patients with ischemic cardiomyopathy and implantable cardioverter defibrillator (ICD).

Methods. This was a single-center retrospective study. A total of 382 medical records of patients from the period between 2019 and 2022, who underwent ICD implantation as part of primary prevention of sudden cardiac death at National Centre of Cardiovascular Surgery, were analyzed. Seventy-four patients were selected for the study. Observation was conducted through in-person examinations and remote monitoring. Endpoints evaluated included overall mortality and arrhythmic events. The cause of death was determined based on the “Promed” medical database. Patients who reached a specific endpoint constituted the case group, while those who did not reach any endpoint formed the control group.

Results. During the observation period, arrhythmic events were registered in 26 patients (35.1%), with a total of 27.1±13.2 events. Twenty-one patients (28.4%) deceased. In univariate regression analysis, the presence of LGE, the extent of LGE (%), and the number of segments with LGE served as predictors of ICD activation and overall mortality. Two multivariate logistic regression models were constructed. ROC curves were used to determine the quality of the regression model, with an area under the curve of 0.807 for ICD activation and 0.789 for mortality. The highest sensitivity and specificity of the method were observed with a LGE value equal to or greater than 14% for ICD activation (sensitivity 81%, specificity 75%) and 26% for overall mortality (sensitivity 89%, specificity 64%).

Conclusion. Substantiated ICD activations (shock/antitachycardia pacing) were observed in 35.1% of cases, and the overall mortality rate was 28.4%. The association between ICD activation and the extent of LGE occurred when LGE was >14%. The association between overall mortality and the extent of LGE occurred when LGE was >26%.

Aim. To study the potential applicability of transcatheter laser ablation for the destruction of atrial ganglionated plexi (GP) zones and the safety of this technique in relation to inadvertent esophageal damage.

Methods. This was a two-stage investigation: (1) ex vivo experiments: the risk of esophageal damage during ablation on the dorsal (posterior) left atrial (LA) wall was assessed; three swine organ complexes were used, which included the heart, lungs and esophagus; (2) in vivo experiments assessing the effects of laser catheter ablation of GP zones on the inducibility of atrial fibrillation (AF) and changes in atrial effective refractory period - included 13 landrace pigs (average weight 38.8±1.2 kg).

Ex vivo: laser catheter ablations were performed from the endocardial surface of the LA towards the esophagus with a power of 15 watts of varying duration; ablation was performed under thermal scanning of the LA and esophagus; then a macroscopic examination of the myocardial and esophageal walls was performed.

In vivo: before and after catheter laser ablation (15 W) of the GP zones in the right atrium and atrial septum, atrial ERP was assessed with programmed stimulation, and AF induction with high-frequency (33 Hz, 2 min) stimulation was evaluated. At the end of the experiment, the animals were euthanized, and the heart and lungs were collected in a single unit.

Results. Ex vivo experiments: in two cases, damage to the endocardium of the LA was detected at an exposure time of 30 s. Damage to the esophagus was observed with a longer exposure time (> 30 seconds) with a 11.3-15.4°C increase in temperature. In the in vivo experiments, 78 laser applications (6±1 in one swine) were delivered to the posterior wall of the right atrium and atrial septum. Atrial effective refractory period was not altered after ablation (183±20 ms vs 186±18 ms, P=0.99). At the baseline, AF was induced in 12 out of 13 animals (92%). After ablation, AF was induced in 7 animals (54%) (P=0.03). There was a trend toward a decrease in the duration of AF after laser ablation of GP zones (18 [5; 141] vs. 2 [0; 14] s after ablation, P=0.06). Transmural damage was observed in 46% of the hearts. No damage to extra-cardiac structures was detected.

Conclusion. Ex vivo, laser ablation on the dorsal (posterior) wall of the LA with a power of 15 W and duration <30 s does not lead to visible damage to the esophagus. Laser ablation of atrial GP zones is feasible and reduces the inducibility of AF. No change in atrial effective refractory period is detected following GP zones ablation, when performed from the right atrium.

Arrhythmogenic right ventricular dysplasia is a hereditary cardiomyopathy - a common cause of sudden cardiac death in children and young adults. Loeys-Dietz syndrome is an ultra-rare connective tissue disorder characterized by aneurysms of the aorta and other large arteries, arterial tortuosity, and joint hypermobility and is associated with pathogenic variants in genes encoding protein components TGF-β pathway. We present a rare case of a two-abovementioned genetic disorders combination in a proband with a complex and rapidly progressive cardiovascular syndrome.

We present a severe disease progression observed in a 13-year-old patient diagnosed with Marfan syndrome and associated cardiac rhythm disorders, including polymorphic ventricular premature contractions and persistent ventricular tachycardia resistant to a wide range of antiarrhythmic medications. We conducted an analysis of contemporary perspectives on the etiology of ventricular tachyarrhythmias and their impact on the prognosis of patients with Marfan syndrome. Conclusions were drawn regarding the selection of treatment strategies for this specific patient population.

The article presents a clinical observation of a patient with episodes of phrenic nerve stimulation after inadvertent permanent ventricular pacing from the middle cardiac vein. The methods of early diagnosis of this complication and techniques for its prevention are described.

A clinical case of cryoballon ablation of pulmonary veins in a patient with atrial fibrillation with congenital heart disease: persistent left superior vena cava, atresia of the superior vena cava. The methods of investigation at the preoperative stage are described, which allow to plan the operation in advance, taking into account the peculiarities of the confluence of the main veins into the heart, and also some technical features of cryoballon ablation surgery are emphasized.

The use of early rhythm control and catheter ablation is an actively developing direction in the treatment of atrial fibrillation. The review presents studies published from 2021 to 2024, the results of which have the potential to strengthen evidence on the early rhythm control and allow to expand the recommendations for the use of catheter ablation with evidence­based medicine principles.

The review summarizes the most update knowledge on the resting ECG QT-interval physiology, current measurement standards and interpretation.

Terminological problems associated with the definition of intra- and interatrial conduction disorders, the possibility of forming complete interatrial block and criteria for its electrocardiographic diagnosis are discussed.