Purpose: To perform instrumental and morphologic diagnostics of «idiopathic» arrhythmias’ etiology by Endomyocardial Biopsy (EMB) of right ventricle and to estimate effect of diagnosis-based treatment.
Methods: 19 patients (9 women and 10 man, 42.6±11.3 years) with 14 resistant to antiarrhythmics including amiodarone, «idiopathic» arrhythmias (84.2% with atrial fibrillation, AF) have undergone EMB with virus detection (PCR); anti-heart antibodies were also measured as well as Echo-CG, myocardial perfusion scintigraphy, CT, MRI, coronary angiography.
Results: EMB allowed to diagnose myocarditis in 12 patients (1 - parvovirus ?19 and 1 - Epstein-Barr virus +), with signs of immune cytolisis (n=3) and mytosis (n=1). In two patients productive vasculitis prevailed (regarded as systemic). Also primary cardiomyopathy (disarray of myocytes) – 2 patients, including 1 with positive virus herpes type 6; parvovirus ?19 positive endomyocarditis, ARVD, Fabry disease were revealed. In the latter two cases, the diagnosis was confirmed by DNA diagnostics (mutations in genes X-GAL, DSG2, DES identified). The most useful methods of myocarditis diagnostics were: specific antinuclear antibodies (sensitivity 78.6%, positive predictive value 91.7%) and general level of anti-heart antibodies. Also defects of perfusion (50%), moderate enlargement of the left atrium (52.6%), mild regurgitation (36.8%), early repolarization (26.3%), pericardial effusion (10.5%) have been revealed. MRI clearly detected signs of ARVD. We have developed an algorithm for nosologic diagnostics of «idiopathic» arrhythmias. In 15 patients therapy of myocarditis/vasculitis was administered: antiarrhythmic drugs, corticosteroids (n=14, 31,1±12,5 mg/day), hydroxychloroquine 200 mg/day (n=15), azatioprine 150 mg/day (n=2), gancyclovir or acyclovir (n=4), IV immunoglobulin (n=2). The average follow-up was 48,0 [31,0; 62,0] months. Decrease of AF frequency (from several times per day to £1 per month) was noted in 56.3 % of patients; in one case stress-induced left bundle branch block disappeared; none of the patients who received immunosupressive therapy had AF transformation in the chronic form. Aggravation of arrhythmia due to infection or therapy withdrawal was noted in 60%. In 5 patients (including those with ARVD) RF ablation was successfully performed; 2 pacemakers and 1 ICD (in patient with ARVD) were implanted.
Conclusions: EMB revealed the immune-inflammatory nature of «idiopathic» arrhythmias (AF) in 78.9% of patients and genetic cardiomyopathy in 21.1%; diagnosis-based therapy has been proved to be effective.