Introduction: Pericardial fluid is enriched with biologically active molecules of cardiovascular origin including microRNAs. Investigation of the disease-specific extracellular microRNAs could shed light on the molecular processes underlying disease development. Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart disease characterized by life-threatening arrhythmias and progressive heart failure development. The current data about the association between microRNAs and ARVC development are limited.Methods and Results: We performed small RNA sequence analysis of microRNAs of pericardial fluid samples obtained during transcutaneous epicardial access for ventricular tachycardia (VT) ablation of six patients with definite ARVC and three post-infarction VT patients. Disease-associated microRNAs of pericardial fluid were identified. Five microRNAs (hsa-miR-1-3p, hsa-miR-21-5p, hsa-miR-122-5p, hsa-miR-206, and hsa-miR-3679-5p) were found to be differentially expressed between patients with ARVC and patients with post-infarction VT. Enrichment analysis of differentially expressed microRNAs revealed their close linkage to cardiac diseases.Conclusion: Our data extend the knowledge of pericardial fluid microRNA composition and highlight five pericardial fluid microRNAs potentially linked to ARVC pathogenesis. Further studies are required to confirm the use of pericardial fluid RNA sequencing in differential diagnosis of ARVC.

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.

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Funding Acknowledgements Type of funding sources: None. Background Wearable monitors and external smart-phone enabled devices represent the new era in remote patient management during covid-19 pandemy. There is growing evidence showing that arrhythmias are one of the major complications of SARS-CoV-2 infection especially in high risk group of patients.  Methods We enrolled 34consecutive patients with confirmed diagnosis of SARS-CoV-2 (mean age62.45 ± 5.25years, 16male). Remote wireless rhythm monitoring was performed using portative ECG sensor.Average follow-up period was 21 days during in-hospital stage and 2 months after discharge. Results Among hospitalized patients with verified SARS-CoV-2 some presented different arrhytmias before admission (9 patients had atrial fibrillation and 11 patients had history of ventricular extrasystoles and non-sustained ventricular tachycardia). One patient underwent cardiac transplantation 1.5 years ago (female 38 years old with a history of dilated cardiomyopathy) and one patient had implanted CRTD device as primary prevention (male 54 years old with a history of myocardial infarction and low LVEF 28%). Other 12 patients did not experience any cardiac arrhythmias before admission. During monitoring period one patient demonstrated asymptomatic pauses longer than 6 seconds (Figure 1) revealed by portative device. After 2 months of follow up he continued to have hemodinamycally significant rhythm pauses and underwent pacemaker implantation. One patient had spontaneus AF conversion into sinus rhythm (Figure 2) also confirmed by wireless monitoring. Other patients did not demonstrate clinically significant arrhythmias. The duration of QT interval was also monitored during in-hospital period in all patients, average score was 451 ± 12 msec. Conclusions Using of wearable electronic devices may contribute to better monitoring of the state of patients and control of symptoms. Abstract Figure. Hemodynamically significant rhythm pause

Introduction. Radiofrequency ablation (RFA) is an established treatment of post-myocardial infarction ventricular tachycardia (VT). Endocardial VT ablation can be insufficient for VT termination when the scar is intramural/epicardial.Purpose: to assess the extent of epicardial electrophysiological VT substrate in patients with remote myocardial infarction.Materials and methods. Thirteen patients with sustained postinfarction VT, who signed an informed consent, were included into the study. All patients underwent full clinical evaluation. Electroanatomical voltage bi- and unipolar mapping of endocardial and epicardial surfaces was performed. Maps were evaluated for the presence of low-voltage areas and local abnormal ventricular activity (LAVA). RFA was performed at LAVA sites. The end-point of the procedure was scar LAVA abolition and VT noninducibility (procedure success). VT recurrence was detected using an implantable cardioverter-defibrillator and/or ECG monitoring.Results. Epicardial access was successful in 12 patients. Epicardial access was performed at a first procedure in 7 patients, 4 patients had a history of previous endocardial ablation. Epicardial LAVA sites were detected in 9 patients. Endocardial and epicardial arrhythmogenic substrate localization coincided in 8 patients. One patient had only epicardial scar, 1 patient had only septal endocardial scar. In one patient LAVA sites had different localizations on epicardial and endocardial maps. Acute ablation success was noted in 12 patients.Conclusion. In our patient group transmural scar and epicardial electrophysiological arrhythmogenic substrate was detected in 82% of cases. Isolated endocardial ablation may be unsuccessful, in such cases epicardial mapping and ablation might be useful.