Guidelines for the diagnosis and treatment of circulatory diseases in the context of the COVID-19 pandemic

Invasive electroanatomical mapping of polymorphic and unstable ventricular arrhythmias is a complex and laborious task. Noninvasive epi-endocardial ElectroCardioGraphic Imaging (ECGI) is a novel beat-to-beat mapping technique. The present work is a second part of single-center single-blind cross-sectional study to verify epi-endocardial ECGI accuracy. This part is particularly dedicated to investigate ECGI accuracy during right ventricular endocardial pacing followed by polygon model quality assessment and detailed analysis of cumulative effect of many different factors.Methods. 37 patients with previously implanted pacemakers were enrolled in the study. All patients underwent epiendocardial ECGI mapping (Amycard 01C EP Lab, Amycard LLC, Russia - EP Solutions SA, Switzerland) during right endocardial ventricular pacing. The data obtained from torso and ECG-gated cardiac computed tomography (Somatom Definition 128, Siemens AG, Germany) were used to create three-dimensional ventricular models. Geodesic distance between noninvasively reconstructed early activate zone on the isopotential maps and RV reference pacing site were measured to evaluate ECGI accuracy for each patient.Results. The mean (SD) geodesic distance between noninvasively reconstructed and reference pacing site was 23 (14) mm for RV epicardial models and 9 (12) for RV endocardial surface of epi-endocardial models, median (25-75% IQR) - 21 (11-32) мм and 4 (2-8) mm respectively. ECGI accuracy on RV endocardial surface of epi-endocardial models was significantly better than on epicardial models (p <0,001). At the same time, there were no significant associations between cardiac CT, pacing parameters, clinical characteristics and accuracy values.Conclusions. The main results showed a possibility of novel epi-endocardial ECGI mapping to detect RV focal arrhythmias with high accuracy (median 3 mm) and to recognize endocardial localization with high percent of probability (more than 94%) comparable with invasive electroanatomical mapping. Therefore, this study confirms sufficient accuracy of epi-endocardial ECGI mapping technology for non-invasive topical diagnosis of RV focal arrhythmias.

Aim. To evaluate the effect of atrial fibrillation (AF) catheter ablation (CA) on long-term freedom from AF and left heart reverse remodeling in patients with heart failure with reduced ejection fraction (HFrEF).Methods. There were 47 patients (mean age 53.3 ± 10 years, 39 males) enrolled into single-center observational study, with left ventricular ejection fraction (LVEF) <40 %. Patients underwent CA for AF refractory to antiarrhythmic drugs. Baseline clinical data and diagnostic tests results were obtained during personal visits and / or via secure telemedical services. Personal contact with evaluation of recurrence of AF and echocardiographic values was performed with 30 (64 %) patients.Results. Paroxysmal AF was present in 12 (40 %) patients, persistent – in 18 (60 %). During mean follow-up of 3 years (0.5–6 years) redo ablation was performed in 9 patients (30 %) with average number of 1.3 procedures per patient. At 6 months 24 (80 %) patients were free from AF, at last follow-up – 16 (53 %). The mean time to first recurrence following CA was 15.6±13.3 months. Follow-up echocardiography revealed significant LVEF improvement (р<0,0001), reduction of left atrium size (р<0,0001), left ventricle end-diastolic volume (р<0,002) and left ventricle endsystolic volume (p<0,0001) and mitral regurgitation (р=0,001).Conclusion. AF CA in patients with HFrEF is associated with improvement in systolic function and left heart reverse remodeling. Durable long-term antiarrhythmic effect often requires repeated procedures.

Aim. To determine quantitative criteria for assessing the therapeutic benefits and the most informative time frames after cardiac resynchronization therapy (CRT) to assess its long-term effectiveness (1, 2, 3 years of follow-up) based on retrospective analysis. To assess the CRT effectiveness, parameters of left ventricular (LV) reverse remodeling and signs characterizing the clinical CRT response were considered.Material and methods. This single-center, retrospective, non-randomized study included data from 278 patients with implanted CRT devices. Quantitative criteria for assessing CRT effectiveness were determined using a two-step cluster analysis of patients 1, 2, and 3 years after CRT by LV reverse remodeling parameters.Results. In the dataset with satisfactory division accuracy, after the first year, two clusters were identified, which are conventionally named as “non-responders” and “responders”. Two and three years after therapy, patients were classified into three clusters: “non-responders”, “responders” and “super-responders”. For the obtained clusters, we found cutoff values for LV reverse remodeling parameters, which can be used as criteria for response to therapy.The study identified the most informative time frames for assessing the postoperative CRT effectiveness 1, 2, 3 years after the surgery. At the same time, the clinical response to therapy is manifested earlier in comparison with the reverse LV remodeling.Despite the high divisibility of patients into responders and non-responders, predictive models of CRT effectiveness created using the available data from standard diagnostic protocols for heart failure patients have insufficient accuracy to be used for making decisions on therapy appropriateness. This circumstance indicates the need to receive additional data to improve the forecasting quality.Conclusion. The study revealed a period for assessing the clinical response and changes in LV reverse remodeling after CRT surgery, which is important for the optimal choice of postoperative therapy. It has been shown that in most cases, one year after surgery is sufficient to assess the clinical response, and the process of LV reverse remodeling can last up to two years on average.When assessing the CRT effectiveness by reverse remodeling, along with a change in LV end-systolic volume (ESV), it is necessary to take into account LV end-diastolic volume (EDV) changes. The change in LV ejection fraction showed a significantly lower value among the analyzed parameters in assessing the CRT effectiveness. Based on the cluster classification of patients, a dividing rule was established for responders and non-responders in the first and second years after surgery with an accuracy of 97%: a decrease in LV ESV and EDV by 9% or more compared to preoperative values.

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