Background Early recurrences of atrial arrhythmias (ERAA) after atrial fibrillation (AF) catheter ablation do not predict procedural failure. A well-demarcated homogeneous lesion delivered by cryoballoon is less arrhythmogenic, and the recommended three-months blanking period may not refer to cryoballoon ablation (CBA). Objective We aimed to evaluate the predictive role of ERAA after second-generation CBA using an implantable loop recorder. Methods This prospective observational study enrolled 100 patients (58 males, median age 58) with paroxysmal/persistent AF undergoing pulmonary vein (PV) CBA using second-generation cryoballoon with simultaneous ECG loop recorder implantation. The duration of follow-up was 12 months, with scheduled visits at 3, 6 and 12 months. Results 99 patients from 100 completed the 12-month follow-up period. ERAA occurred in 31.3 % of patients. 83.9 % of patients with ERAA also developed late recurrences. The 12-month freedom from AF in patients with ERAA was significantly lower than in those without ERAA (p < 0.0001). Non-paroxysmal AF and longer arrhythmia history were associated with increased risk of both early (HR 3.27; 95 % CI 1.32–8.08; p = 0.010 and HR 1.0147; 95 % CI 1.008–1.086; p = 0.015, respectively) and late recurrences (HR 3.89; 95 % CI 1.67–9.04; p = 0.002 and HR 1.0142; 95 % CI 1.007–1.078; p = 0.019, respectively) of AF. ERAA were another predictor for procedural failure (HR 15.2; 95 % CI (6.42–35.99; p = 0.019). Conclusions ERAA occurred in the third of the patients after PV second-generation CBA and are strongly associated with procedural failure. Longer duration of AF history and persistent AF are independent predictors of AF’s early and late recurrence.

Adenovirus (AdV) has been suggested to be involved in pathogenesis of atrial fibrillation (AF). We aimed to evaluate an association between AdV-specific immunoglobulins G in the serum (AdV-IgG) and AF. The present case-control study comprised two cohorts, including cohort 1 of patients with AF and cohort 2 of asymptomatic subjects. Initially, two groups, MA and MB, were selected from the cohorts 1 and 2, respectively, for serum proteome profiling using an antibody microarray to identify possible relevant protein targets. The data of microarray analysis indicated a possible overall increase in the total adenovirus signals in the group MA vs. group MB, suggesting potential relevance of adenoviral infection to AF. Then, the groups A (with AF) and B (control) were selected from the cohorts 1 and 2, respectively, to assay the presence and levels of AdV-IgG- by ELSA. The prevalence of AdV-IgG-positive status demonstrated a 2-fold increase in the group A (AF) compared with that in the group B (asymptomatic subjects); odds ratio 2.06 (95%CI: 1.11–3.84; P = 0.02). The prevalence of obesity demonstrated an approximately 3-fold increase in AdV-IgG-positive patients of the group A compared with that in AdV-IgG-negative patients of the same group A (odds ratio 2.7; 95% CI: 1.02–7.1; P = 0.04). Thus, AdV-IgG-positive reactivity was independently associated with AF, and AF was independently associated with BMI, indicating that adenoviral infection may be a possible etiological factor for AF.

Aim. To determine the clinical, morphological, and biochemical pre­dictors of substrate-specific, non-vein-dependent atrial fibrillation (AF) by morphological and immunological examinations in patients with recurrent AF after pulmonary vein (PV) isolation.Material and methods. The study included 100 people (58 men and 42 women) with paroxysmal (n=89) and persistent (n=11) AF with a mean age of 58,2±9,4 years. After the primary operation, 15 people withdrew from the study due to refusal of reintervention, and 1 person withdrew due to suppuration of loop recorder bed and its explantation. A total of 100 patients underwent primary cryoballoon PV isolation with myocardial biopsy from the interventricular and interatrial septa, while 60 patients had subsequent hematoxylin-eosin and Van Gieson stains. Also, 100 patients were simultaneously implanted with ECG loop recorders for AF monitoring and blood was taken (before the intervention) for subsequent analysis of inflammation markers and antimyocardial antibodies. Patients underwent clinical observation during the year (visits after 3, 6, 12 months). Patients with relapses were referred for repeat electrophysiological examination and segmental ablation if PV ruptures were detected. After repeated intervention, the follow-up period was extended for a year with the same schedule of visits. According Two groups of patients were formed: without relapses (vein-dependent AF, group I) and with relapses (non-vein-dependent AF, group II), despite the achieved PV isolation as a result of 1 or 2 operations.Results. An analysis of morphological changes showed that an increase in AF recurrence risk by an average of 6,14 times (95% confidence interval: 1,14-47,6 (p=0,0462)) is associated with stage 2 interventricular septal fibrosis. Lymphocyte infiltration of the interventricular septum was associated with higher AF recurrence by an average of 9 times (95% confidence interval: 0,89-95,37) (p=0,0519).Among the laboratory parameters, a significantly higher concentration of the N-terminal pro-brain natriuretic peptide and a significantly lower concentration of antimyocardial antibodies were found in the group of patients with recurrent AF after LV isolation (p=0,0101).Conclusion. Inflammatory myocardium changes are an important link in the pathogenesis of AF and are associated with its recurrence.

Aim. To study the association between morphological changes and comorbidities and atrial fibrillation (AF) catheter ablation efficacy, and to evaluate morphological predictors of AF recurrence in patients with durable pulmonary vein isolation (PVI) after catheter intervention.Material and methods. Fifty-four patients with paroxysmal/persistent AF without severe structural heart disease were enrolled in this study who underwent primary pulmonary vein cryoballoon ablation (CBA) with simultaneous implantation of an electrocardiogram loop recorder (Medtronic Reveal XT) and interatrial/interventricular septum biopsy. The follow-up duration was 12 months with scheduled 3, 6 and 12 month visits. Patients with recurrent AF were referred for redo procedure, where the PVI durability was assessed. The follow-up duration after the second procedure was also 12 months. The patients were divided into two groups: patients without recurrent AF and patients with recurrent AF after two catheter interventions.Results. In interventricular septum biopsy samples we found the morphological criteria of myocarditis in 70% of the patients (n=34). Individual morphological changes were detected in all patients. The most common types were cardiomyocyte hypertrophy — 98,1% (n= 52), overcrossing of cardiomyocytes — 77,4% (n=41) and lymphohistiocytic infiltration of the interstitium by more than 14 cells — 75,5% (n=40). Patients with persistent AF were significantly more likely to have endothelial cell swelling (55% vs 45%, p=0,022). Interstitial tissue edema was the only morphological parameter significantly associated with AF recurrence (p=0,03).Conclusion. In patients with AF and no structural heart disease who underwent drug-resistant AF cryoballoon ablation, morphological changes in the myocardium of the atria and ventricles are detected in 100% of cases. The predominant biopsy diagnosis is myocarditis. Morphological signs of the inflammatory process activity, as interstitial tissue edema are associated with the high incidence of non-venous AF. Further preoperative evaluation is needed to identify patients with non-venous atrial fibrillation, which will increase the effectiveness of interventional approach.