Aim of the study was to elucidate nosological nature of "idiopathic" arrhythmias by means of right ventricular endomyocardial biopsy (EMB) and to assess effect of etiotropic and pathogenetic treatment.
Material and methods: We included into this study 19 patients (mean age 42.6 +/-11.3 years, 9 women) with atrial fibrillation (AF, n = 16), supraventricular (n = 10) and ventricular (n = 4) extrasystoles (SVE and VE), supraventricular (n = 2) and ventricular (n = 1) tachycardia (SVT and VT), left bundle branch block (LBBB, n = 2), atrioventricular block (n = 2) without structural changes of the heart. In addition to standard examination we performed the following tests: determination of IgG to herpes and Coxsackie B virus, polymerase chain reaction (PCR) for DNA detection of human herpesviruses 1, 2, and 6, Epstein-Barr virus, Varicellae-zoster virus (human herpesvirus 3) and cytomegalovirus in blood; determination of anticardiac antibodies; EMB with subsequent PCR-diagnostics including that of parvovirus B19 and pathomorphological study. DNA diagnostics (n = 4), coronary angiography (n = 6), skin biopsy (n = 1) and some other studies were also performed when indicated.
Results and conclusions: Histological picture was abnormal in all cases. Nosological diagnosis was established in all patients: infectious-immune myocarditis (n = 11), parvovirus positive endomyocarditis (n = 1); systemic vasculitis (n = 2); myocardial vasculitis (n = 1), Fabri disease (n = 1), arrhythmogenic right ventricular dysplasia (ARVD, n = 1), undetermined genetic cardiomyopathy (n = 2). Level of various anticardiac antibodies including antinuclear factor with bovine heart antigen was most valuable for diagnosis of myocarditis (sensitivity 78.6%, prognostic value of positive result 91.7%). The following therapy was used in patients with myocarditis/vasculitis: intravenous or oral acyclovir (n = 10), gabreglobine (n = 2), meloxicam (n = 12), hydroxychloroquine (n = 15 for 15 [7.0; 24.] months), glucocorticosteroids (n = 14 for 18 [4.0; 25.5] months), azathioprine (n = 2). Mean duration of follow up was 4 years (48 [31; 62] months). At baseline 62.5% of patients with AF were resistant to all antiarrhythmic drugs. Treatment of myocarditis resulted in significant reduction of mean frequency of attacks of AF from 8 to 3 points, more than in 40% of patients AF emerged less than once a month and 1 patient had no attacks at all. Disappearance of tachycardia dependent LBBB was also noted. Cardioverter defibrillator and cardiac pacemaker were implanted to patients with ARVD and Fabri disease, respectively. EMB helped to establish immunoinflammatory and genetic diseases as causes of idiopathic arrhythmias (in 78.9 and 21.1% of patients, respectively). Antiviral immunosuppressive therapy of myocarditis allowed to increase efficacy of antiarrhythmic therapy in resistant patients and when necessary to optimize their preparedness to interventional treatment.