To study etiology of non-coronary ventricular tachyarrhythmia (VTA) based on the assessment of the endomyocardial biopsy data, 87 patients aged 39.9±1.7 years (50 men; 57.5%) were examined. The study group included 41 patients (47%) with episodes of sustained ventricular tachycardia (VT) and 46 patients (53%) with ventricular premature contractions (VPC) and/or non-sustained VT. Electrocardiography, 24 hour ECG Holter monitoring, echocardiography, magnetic resonance tomography with contrasting and in the fat suppression mode, stress test, and coronary angiography to exclude the VTA ischemic origin were performed. The endomyocardial biopsy was carried out in the area of surgical treatment of the arrhythmia, which included catheter ablation and/or implantation of a cardioverter-defibrillator. According to the data of endomyocardial biopsy, arrhythmogenic cardiomyopathy/right ventricular dysplasia (ACRVD) was diagnosed in 29 patients (33%), myocarditis, in 34 patients (39%), and postmyocarditic cardiosclerosis, in 24 ones (28%). The histological study of myocardial biopsy samples of the patients with ACRVD showed lipomatosis, microfocal fibrosis, as well as dystrophy and atrophy of the right ventricle muscular fibers. Signs of active myocarditis were found in 7 patients, of chronic myocarditis, in 2 ones. The relative area of lipomatosis was 34.3±14% (3 90%); 32.7±13.4% in patients without myocarditis and 42.1±22.3% in patients with myocarditis. The relative area of fibrosis was 36.7±18% (2 90%); 30±15% in patients without myocarditis and 37.2±17.2% in patients with myocarditis. Thus, the endomyocarial biopsy permits one to determine etiology of VTAs considered “idiopathic” during the standard (typical) non-invasive study. The most frequent causes of non-coronary ventricular arrhythmias were ACRVD (33%), myocarditis (33%), and post-myocarditic fibrosis (28%).

Aim. To determine the clinical features of arrhythmogenic right ventricular dysplasia (ARVD) in recipients on heart transplant waiting list (WL) and after a heart transplantation (HTx). Material and methods . From January 2010 to December 2018, we included 192 recipients in heart transplant waiting list (HTx WL) on behalf of Almazov National Medical Research Center. ARVD was diagnosed in 4 subjects (F Marcus et al. criteria, 2010). All 4 patients (female, mean age 46,5 years-old (16-54-year-old)) underwent HTx. Prior to HTx, arrhythmias (atrial fibrillation, atrial flutter) were diagnosed in 3 recipients. In patient №2, pacemaker in VVI mode was implanted due to sick sinus syndrome (SSS) and tachycardia-bradycardia syndrome and others underwent ICD implantation. Results. Survival after HTx was 30,9 (3,9-46,2) months. All recipients were treated with triple-drug immunosuppressive therapy (calcineurin inhibitors, mycophenolic acid, steroids) and induction with Basiliximab. All patients experienced high sensitivity to immunosuppressive therapy (agranulocytosis), and therefore a colony-stimulating factor was administered to all of them. After immunosuppression reduction (Tacrolimus plus Methylprednisolone) agranulocytosis did not recur. Conclusion. ARVD is a rare disease in the structure of end-stage heart failure in recipients in HTx WL. An examination of this pathology is necessary to manage patients on-time with surgical treatment (ICD, HTx). According to our results, causal variants in desmosome genes were determined in 1 from 4 patients and simultaneous presence of two unique genetic variants in the RKR2 gene were found in one. A special feature of post-HTx management was the development of agranulocytosis, which once again underlines the need for a personalized approach to the selection of the immunosuppressive therapy.

Objective. To study the etiology of nonischemic ventricular arrhythmias and to improve diagnostic evaluation of inlammatory myocardial disease using endomyocardial biopsy.Design and methods. We performed 100 endomyocardial biopsies during catheter ablation in patients with nonischemic ventricular arrythmias. Results. Myocarditis was veriied in 58 cases, and postinlammatory ibrosis — in 24 cases. Twenty three patients (67 %) demonstrated active myocarditis, 1 (2,9 %) had chronic active myocarditis, and 10 subjects (29 %) — chronic non-active myocarditis. Conclusion. Endomyocardial biopsy contributes to better veriication of the etiology of ventricular arrhythmias. Late gadolinium enhancement during magnetic resonance imaging shows 74 % sensitivity and 46,9 % speciicity in the evaluation of myocarditis, and 52,4 % sensitivity and 38,9 % speciicity in veriication of postinlammatory ibrosis. Presence of CD-8+ cells, Ig M, patchy dystrophin expression can be additional features for veriication of active myocarditis.

To assess causes of sudden cardiac death, analyzed were autopsies, autopsy reports, police reports, and questionnaires completed by relatives and/or witnesses of fatal events; performed were cardiac organometry, histological, morphometric, and immunohistochemical assessments of the ventricular myocardium, heart valves, and coronary arteries in 128 adolescents and young adults aged 14 35 years.