[Idiopathic arrhythmias: possibilities of complex nosological diagnosis, and differentiated treatment].

Aim: of the study was to elucidate nosological nature of "idiopathic" arrhythmias by means of complex clinical-morphological examination and to assess efficacy of differentiated (including etiotropic and pathogenetic) treatment.

Material And Methods: We examined 190 patients (117 women, mean age 45.33 ± 14.84 years) with "idiopathic" arrhythmias: atrial fibrillation (38.9%) (AF,) and flutter (11.1%), supraventricular (44.7%) and ventricular (55.3%) extrasystoles (SVE and VE), bouts of ventricular tachycardia (15.8%), atrioventricular block (22,6%) et al. Mean number of antiarrhythmic drugs per patient was 3 (from 1 to 8). Examination included Holter ECG monitoring, echocardiography, determination of anticardiac antibodies (97.4%) and markers of cardiotropic viruses (87.4%), treadmill test (26.3%), transesophageal cardiac pacing (12.1%), electrophysiological investigation (10%), multispiral computed tomography (22.1%), magnetic resonance tomography (21.6%), scintigraphy (27.4%), coronary angiography (10.0%), endomyocardial biopsy (EMB) (10.0%), DNA diagnostics (8.9%).

Results: EMB revealed immune-inflammatory (myo/endocarditis, systemic/myocardial vasculitis) or genetic pathology in 78.9 and 21.1% of cases, respectively. Level of anticardiac antibodies (including specific antinuclear factor) most closely correlated with EMB findings. On the basis of comparison of EMB data with data of complex examination we created algorithm of nosological diagnostics in "idiopathic" arrhythmias. According to nosology all patients were distributed in the following way: 1) chronic infectious-immune myocarditis (n=144, 75.7%), morphologically verified in 14, viral in 27 patients; 2) genetic cardiomyopathy (n=15, 7.9%), morphologically verified in 4, virus positive in 1 (arrhythmogenic right ventricular dysplasia, non-compaction myocardium, Fabri disease, Brugada syndrome, undetermined); in 4 patients mutations in plakophilin 2, desmoglein, desmin, -galactosidase A genes were found; 3) combination of genetic diseases with myocarditis (n=18; 9.5%) including viral (n=3); 4) isolated myocardiodystrophy (tonsillogenic< dyshormonal, n=3, 1.6%); 5) proper idiopathic arrhythmias (n=10, 5.3%). Therapy of myocarditis included antiviral (43.2%) and immunosuppressive (76.3%) drugs. Cardiotropic and antiarrhythmic therapy was also administered. Only in patients with myocarditis it was possible to withdraw effective antiarrhythmic (16.7%) and to improve effect of previously ineffective drugs. Surgical treatment (implantation of pacemaker or cardioverter-defibrillator, radiofrequency ablation) was more frequently used in patients with genetic (39.4%) and idiopathic arrhythmias (53.8%) than in patients with myocarditis (16.0%).

Conclusion: Etiology of idiopathic arrhythmias can be established in most cases. Their main causes are immune-inflammatory diseases, genetic cardiomyopathies and their combination. Therapy of myocarditis improves antiarrhythmic activity of treatment, in some patients allows to withdraw antiarrhythmic drugs, decrease requirements in surgical treatment and to optimally prepare patients to radiofrequency ablation.