Aim. To study the role of left atrial posterior wall (LAPW) isolation in increasing the clinical efficacy of radiofrequency ablation (RFA) in patients with persistent atrial fibrillation (PeAF) during electrophysiological studies.

Methods. A single-center randomized prospective study. From February 2020 to February 2021, 35 procedures were performed on patients with PeAF. Patients were randomized into two groups - pulmonary vein isolation (PVI) plus LAPW isolation according to the “box lesion” scheme (the first group) and the PVI-only group (the second group). If it was impossible to achieve LAPW isolation, “debulking” was performed. After 3 months, regardless of the clinical status, EPS and RFA of the reconnection zones were performed.

Results. The full study protocol study was completed by 30 patients - 14 in the first group and 16 in the second group. The characteristics of the patients in the groups did not differ statistically. The duration of the primary and redo procedures, as well as the RFA time during the primary procedure in the first group is significantly longer than in the second group. Pulmonary veins were isolated in all patients participating in the study. In the first group, LAPW isolation was achieved only in 21.4% of cases (3 patients), in the remaining 78.6% of cases (11 patients) “debulking” was performed. PVI in the first group was maintained in 78.6% of cases (11 patients), and in the second group in 56.2% (9 patients), the difference was not statistically significant (p=0.209). In the first group, LAPW isolation was maintained in 28.6% of patients (4 patients). All patients with reconnection underwent RFA with the restoration of the conduction block. In the midterm (440±82.1 days) of follow-up, the sinus rhythm was preserved in the first group in 11 patients (78.5%), and in the second group in 13 (81.2%) patients. There was no statistically significant difference between the groups (OR 0.846 95% CI 0.141-5.070, p=0.641).

Conclusions. In our study, LAPW isolation in addition to PVI in patients with PeAF did not improve the efficacy of treatment with a significantly longer duration of procedure and RFA time.

Aim. To evaluate intraoperative doses of administered heparin to achieve the target value of activated clotting time (ACT) in patients receiving preoperative anticoagulant therapy with warfarin or one of the non-vitamin K antagonists oral anticoagulants (NOAC).

Materials and methods. The study was of a retrospective. Inclusion criteria: patients with atrial fibrillation (AF) who have indications for catheter ablation in accordance with national clinical guidelines; age 18-75 years; absence of thrombus and the effect of echocontrasting 3-4 stage in the left atrium cavity according to transesophageal echocardiography or computed tomography with contrast enhancement; regular intake of anticoagulants prescribed at least 3 weeks before hospitalization. Exclusion criteria: additional intake of antiplatelet drugs; contraindications to the anticoagulant therapy, including intolerance to the components of drugs; weight more than 100 kg. According to the criteria for inclusion in the study 279 patients were included (211 of them received warfarin and 68 received one of the NOAC). The mean age of the patients was 59.2±8.9 years, the body mass index was 59.2±8.9 kg/m². Among them, men accounted for 155 (55,6%), diabetes mellitus was diagnosed in 28 (10%), arterial hypertension - in 224 (80.3%), coronary heart disease - in 103 (36.9%). Paroxysmal AF was observed in 185 (66.3%) of patients, persistent AF - in 77 (27.6%), and long-standing persistent AF - in 17 (6.1%). To ensure maximum comparability of the groups pseudorandomization was performed with the formation of 67 pairs of patients.

Results. A group of patients taking warfarin for preoperative preparation required lower doses of heparin to achieve the target AСT and amounted to 14.8±5.1 thousand ME compared to 17.9±4.4 thousand ME in the NOAC group (p=0.0001). Despite the lower dose of heparin the ACT level in the warfarin group was significantly higher than in patients taking NOAC (441.5±203.4 sec. and 345.4±148.8 sec. accordingly, p=0.0001).

Conclusions. A significantly lower dose of heparin was required in the warfarin group to achieve the target ACT (>300) than in the group of NOAC, while the maximum ACT value was higher. Thus, with the standard starting dose of heparin, the target anticoagulation was achieved faster in patients receiving warfarin.

Aim. To investigate the agreement among different response criteria to cardiac resynchronization therapy (CRT) and long-term mortality in patients with congestive heart failure (CHF).

Methods. The study enrolled 141 patients (men 77.3%; women 22.7%) with CHF (65.2% ischemic and 34.8% non-ischemic etiology). Mean age was 58.6 [53.0;66.0] years. All patients had NYHA II-IV, left ventricular ejection fraction (LVEF) ≤35%; QRS ≥130 мs and/or left bundle branch block. Mean follow-up period was 45.0±34.2 months. Response to CRT was defined according to dynamics of NYHA functional class, LVEF, and left-ventricular end-systolic volume (LVESV).

Results. Moderate agreement was found among LVEF and LVESV (Cohen’s k coefficient 0.591±0.068) while we did not find the agreement among echocardiographic criteria and NYHA. Long-term mortality had moderate negative correlation with LVESV (r=-0.486; p

Conclusion. Agreement between different criteria to define response to CRT is poor. The strongest correlation with long-term mortality was found for LVESV. This inconsistency among different response criteria severely limits the ability to generalize results over multiple CRT studies.

Aims. To develop an algorithm for assessing the stage of fibrosis based on high-density endocardial mapping. To study the effect of the stage of left atrial (LA) fibrosis on the results of atrial fibrillation (AF) catheter ablation.

Methods. The study included 64 patients with paroxysmal or persistent AF, who underwent high-density LA mapping and catheter ablation. After the intervention procedure, we analyzed the electroanatomical maps of the left atrium, assessed the prevalence of low-voltage areas according to the developed algorithm. Patients were divided into 4 groups depending on the prevalence of areas of low voltage based on the Utah score.

Results. The follow-up period was 14.5 ± 6.7 months. AF recurrence developed in 18 (28.1%) patients after the ablation procedure. AF recurrence after ablation was more frequent in patients with a low-voltage area of more than 20% than in patients with a low-voltage left atrial area of less than 20%, 6 (15.4%) versus 12 (48%), p=0.02. A logistic regression analysis was performed to identify AF recurrence predictors in the postoperative period. As a result, only widespread areas of low-amplitude activity were an independent predictor of AF recurrence after the pulmonary veins isolation, this predictive model was significant (p=0.026). Significant statistical differences between groups I, II and III,I V are the ejection fractions and the duration of the P-wave. Patients with low-voltage regions have lower left ventricular ejection fraction (62.8±6.9% versus 58.1±5.7%, p=0.01), and longer P-wave duration (84.7±8,2 ms versus 101.5±11.0 ms, p=0.01).

Conclusion. LA high-density mapping before AF ablation makes it possible to determine the prevalence of low-voltage areas. After regression analysis, it was proved that common low-voltage areas are an independent predictor of AF recurrence after pulmonary vein isolation. Patients with low-voltage areas of more than 20% of the LA surface have longer P-wave duration and lower left ventricular ejection fraction.

A clinical case of successful radiofrequency ablation of ventricular tachycardia with para-Hisian localization of the substrate by access from the right coronary sinus of Valsalva is presented.

We present a case of successful intracardiac echocardiography guided left atrial appendage catheter closure in a patient with esophageal varices using deflectable delivery sheath to improve ICE-catheter stability.

The article presents a clinical case of a young patient living in the Far North for a long time with Frederick’s syndrome and diagnosed of the left atrial appendage thrombosis.

The accurate tachycardia mechanism verification is the most important condition for high effectiveness and safety of the supraventricular tachycardia ablation. Ventricular overdrive pacing - is a simple and useful diagnostic maneuver, frequently used in the supraventricular tachycardia diagnosis. The conditions for its performance and interpretation in the standard and rare situations are described in this review.

Fragments of a transesophageal electrophysiological study of a 35-year-old patient with induction of paroxysmal atrioventricular nodal re-entry tachycardia occurring with three different electrocardiographic patterns are presented.