Aim To compare diagnostic significance of different criteria for complete left bundle branch block (cLBBB) in prediction of reverse left ventricular (LV) remodeling associated with cardiac resynchronization therapy (CRT). Materials and methods This study included 93 patients (men, 81.7 %; mean age at the time of implantation, 56.6±9.3 years). Achievement of a maximum decrease in LV end-systolic volume (ESV) was recorded during the entire follow-up period for evaluation of LV reversibility by CRT. Based on the dynamics of LV ESV, patients were divided into two groups, non-responders (n=27) and responders (n=66). cLBBB was determined by 9 criteria (ESC 2006 and 2013, AHA 2009, Strauss, and MIRACLE, CARE-HF, MADIT-CRT, REVERSE, and RAFT used in large multicenter studies). Results Incidence of cLBBB was significantly higher in the group of responders as demonstrated by the AHA (p=0.001), ESC 2013 (p=0.014), Strauss (p=0.002), MADIT-CRT (p=0.014), REVERSE (p=0.013), and RAFT (p<0.001) criteria. The highest specificity was shown for the AHA and RAFT (92.6 %) criteria, and the highest sensitivity and overall accuracy were shown for the Strauss (80.3 % and 72.04 %, respectively) criterium. The criteria proposed in actual clinical guidelines (AHA and ESC 2013) demonstrated a strong consistency in detecting cLBBB (κ=0.818, 95 % CI, 0.7–0.936; p<0.001). However, the Strauss and ESC 2006 / AHA / ESC 2013 showed the least consistency in identifying cLBBB. For the criteria described in large multicenter studies, consistency in detecting cLBBB was minimal in most cases. However, criteria with moderate or strong consistency were used in the studies, which results have substantiated the use of cLBBB as a selection criterium (MADIT-CRT, REVERSE, and RAFT). Conclusion The reversibility of LV remodeling associated with CRT was different in patients with cLBBB determined by different criteria. All actual cLBBB criteria (AHA, ESC 2013, and Strauss) were significantly more frequently observed in the responder group. Nevertheless, these criteria differed in their sensitivity and specificity. A number of large multicenter studies have used criteria with minimal consistency in detecting cLBBB, which should be taken into account in interpreting results of these studies.

Aim. To assess the prevalence of traditional risk factors and analyze the predictors of recurrent cardiovascular events in patients with acute coronary syndrome (ACS). Material and methods. A total of 482 patients with ACS were included. The follow-up lasted three years. The composite endpoint (CE) included recurrent unstable angina, nonfatal myocardial infarction, repeated percutaneous coronary intervention (PCI), nonfatal ischemic stroke, hospitalization for decompensated heart failure, and cardiovascular death. Results. A high prevalence of traditional risk factors was revealed (dyslipidemia — 467 (96,9%), hypertension — 464 (96,3%), consumption of junk food — 450 (93,4%), sedentary lifestyle — 416 (86,3%)). During the three-year follow-up period, 90 patients had CE. Compared with patients without CE (n=392), patients with CE were significantly more likely to have a long-term CAD (69 (76,7%) vs 241 (61,5%), p=0,007), ACS accompanied by shortness of breath (50 (55,6%) vs 160 (40,9%), p=0,013); they had previously undergone myocardial revascularization (38 (42,2%) vs 116 (29,6%), p=0,024), often by PCI (36 (40,0%) vs 100 (25,5%), p=0,009), especially in the left main coronary artery (LMCA) (6 (6,7%) vs 3 (0,8%), p=0,002); they were more likely to develop in-hospital acute left ventricular failure (11 (12,2%) vs 18 (4,6%), p=0,012), had a lower hemoglobin level and hematocrit (p<0,05 for all); they more often required intensification of lipid-lowering therapy (86 (100%) vs 334 (85,2%), p=0,002), compliance with which was lower (6 (6,7%) vs 105 (26,8%), p<0,001) than in patients without CE. Previous intervention on the left coronary artery, non-compliance with lipidlowering therapy, hematocrit level 3 months and hemoglobin level 1 year after ACS were predictors of recurrent events. The combination of surgery on left coronary artery and non-compliance with lipid-lowering therapy demonstrated significantly less freedom from CE compared with other patients (77,4% vs 94,6%, p<0,001). Conclusion. A high prevalence of traditional risk factors in the population of patients with ACS was revealed, and potential predictors of recurrent cardiovascular events were identified.

Aim . To analyze the prognostic value of 18 electrocardiographic (ECG) markers of left bundle branch block (LBBB) in predicting left ventricular (LV) reverse remodeling in patients receiving cardiac resynchronization therapy (CRT). Material and methods . The study included 98 patients. Depending on the presence of reverse remodeling during CRT, defined as a decrease in LV endsystolic volume ≥15%, the patients were divided into two groups: non-responders (n=33) and responders (n=65). We selected and analyzed 18 ECG markers included in 9 LBBB criteria. Results . Among the ECG markers significantly associated with reverse remodeling during CRT, the absence of q wave in leads V5-V6 demonstrated the highest sensitivity (92,31%), a negative predictive value (70,59%) and overall accuracy (73,47%). Normal internal deviation interval of the R wave in leads V1-V3 was also associated with the best sensitivity (92.31%), while QS with a positive T in lead aVR — the best specificity (69,7%). Discordant T wave demonstrated the highest positive predictive value (80,33%). Multivariate analysis revealed following ECG signs independently associated with reverse remodeling during CRT: QRS complex duration (odds ratio (OR)=1,022; 95% confidence interval (CI): 1,001-1,043; p=0,040); absence of q wave in leads V5-V6 (OR=4,076; 95% CI: 1,071-15,51; p=0,039); discordant T wave (OR=4,565; 95% CI: 1,708-12,202; p=0,002). These ECG findings were combined into a mathematical model that demonstrated high predictive power (AUC=0,81 [0,722-0,898], p<0,001). Once the cut-off point was determined, a binary variable was obtained that showed higher sensitivity, negative predictive value, and overall accuracy when compared with the actual LBBB criteria. The 5-year survival rate among patients with a model value above the cut-off point was 84,4%, while in patients with a value below the cut-off point — 50% (Log-rank test, p=0,001). To improve usability of the model, a mobile application was developed. Conclusion . For the first time, the diagnostic value of ECG markers of LBBB were analyzed and a mathematical model with ECG signs was proposed to predict reverse remodeling in patients receiving CRT.

Aim. To analyze 20 electrocardiographic (ECG) signs of left bundle branch block (LBBB) before and after septal myectomy in patients with hypertrophic cardio myopathy (HCM) and develop a criterion for proximal LBBB based on the selected signs.Material and methods. This retrospective non-randomized study included 50 patients with obstructive HCM who underwent septal myectomy. There were following inclusion criteria: QRS width <120 ms before surgery, transaortic access during septal myectomy, and QRS width ≥120 ms in the early postoperative period. For each patient, ECGs were analyzed before septal myectomy and in the first week after surgery. At the same time, 20 ECG signs proposed earlier in the LBBB criteria were independently assessed.Results. Exsection of a small myocardial area of the basal interventricular septal parts, weighing an average of 4,9±2 grams, led to a significant increase in the QRS width (by 61±14,6 ms) and the prevalence of almost all ECG signs of LBBB. In 100% of cases (n=50), the following signs demonstrated significant dynamics after surgery: (1) midQRS notching or slurring in ≥2 contiguous leads (I, aVL, V1-V2, V5-V6); (2) absence of q wave in V5-V6 and (3) discordant T wave in at least two leads (I, aVL, V5, V6). Based on the design of the study, (4) QRS width ≥120 ms was additionally included. These ECG characteristics were combined into a new criterion for proximal LBBBConclusion. A new criterion for proximal LBBB was developed using the pathophysiological model of iatrogenic conduction block of left bundle branch. Further estimation of this criterion on a set of candidates for CRT with heterogeneous level of LBBB is necessary.

Aim. To assess the relationship between the prolonged PR interval (≥200 ms) and the long-term survival of patients undergoing cardiac resynchronization therapy (CRT).Material and methods. A total of 85 patients (mean age — 55,1Ѓ}9,9 years; men — 81,2%) with NYHA class II-IV heart failure (HF) were examined. The mean follow-up was 34,0Ѓ}21,2 months. Patients with PR<200 ms (n=52) made up group I, with PR≥200 ms (n=33) — group II. Then the patients were divided into subgroups depending on the QRS duration: ≥150 ms (n=33 in group I and n=14 in group II, respectively) <150 ms (n=19 in group I and n=19 in group II, respectively).Results. In patients of group II, a history of myocardial infarction (MI) was more often registered (p=0,005), left ventricular ejection fraction (LVEF) was lower (p=0,032). In a multivariate analysis, MI (OR 3,217; CI 95% 1,188-8,712; p=0,022) and LVEF value (OR 0,869; CI 95% 0,780-0,968; p=0,011) had a significant relationship with the PR interval prolongation (≥200 ms). The survival of patients of group I was 59,6%, group II — 18,2% (Log-rank test p<0,001). According to Cox regression model, the initial left ventricle end-systolic volume (OR 1,012; 95% CI 1,006-1,017; p<0,001), inferior wall MI (OR 1,690; 95% CI 1,131-2,527; p=0,011) and PR interval ≥200 ms (OR 2,179; 95% CI 1,213–3,915; p=0,009) were associated with long-term mortality. In patients with PR≥200 ms, survival rate was low, regardless of the QRS duration (21,4% in patients with QRS≥150 ms, 15,8% in patients with QRS<150 ms; Log-rank test p=0,698) In patients with PR<200 ms, the survival rate of patients with QRS≥150 ms was 72,7%, and for patients with QRS<150 ms — 36,8% (Log-rank test p=0,031).Conclusion. In HF patients, PR interval prolongation (≥200 ms) is associated with long-term mortality increase. The highest survival rates were observed in patients with PR<200 ms and QRS≥150 ms. In patients with QRS≥150 ms, the presence of PR≥200 ms should be considered as an additional criterion for CRT.

Aim. Based on clinical parameters and diagnostic investigations, to create a complex model of personalized selection of patients with heart failure (HF) for cardiac resynchronization therapy (CRT). To establish the diagnostic value of the created model in predicting 5-year survival.Material and methods. The study included 141 patients with HF (men, 77,3%; women, 22,7%). The mean age of patients at the time of implantation was 60,0 [53,0; 66,0] years. All patients had New York Heart Association (NYHA) class II-IV HF, left ventricular ejection fraction (LVEF) ≤35%, and QRS ≥130 ms. Patients were randomly divided into training (n=95) and test (n=36) samples, which were comparable in main clinical and functional characteristics.Results. The index included parameters that had a significant relationship with 5-year survival according to the Cox regression: male sex, prior myocardial infarction, hypertension, QRS <150 ms, no left bundle branch block, PR ≥200 ms with sinus rhythm/absence of radiofrequency ablation in atrial fibrillation, NYHA class III, IV HF, LVEF <30%, left ventricular end-diastolic volume ≥235,0 ml, NT-proBNP ≥2692,0 ng/ml. All variables were scored based on the в-coefficients. In the training sample, a value ≥45 points demonstrated a sensitivity of 82,4% and a specificity of 67,2% in predicting 5-year survival (AUC, 0,873; p<0,001). The index use on the test sample showed comparable results (AUC, 0,718; p=0,020; sensitivity — 71,4%, specificity — 62,5%). Also, in the training sample, the index ≥45 points was associated with1-year survival (sensitivity — 84,6%, specificity — 58,1%, AUC, 0,811; p<0,001).Conclusion. An index of personalized selection for CRT has been created, which makes it possible to accurately predict the 5-year survival rate, as well as the 1-year survival rate, regardless of the current selection criteria.